GuidesWarmup basics

Back from a break: do you need to warm up again?

A mailbox that goes quiet does not keep its standing forever, but it does not lose it overnight either. Here is how long a pause is harmless, what the documentation says, and how to come back without tripping a spam filter.

Updated 5 October 20267 min read

In short

A few days off change nothing. After more than about a month of complete silence, restart low and rebuild over one to two weeks.
The 30-day rule comes from email service providers and applies to dedicated IP addresses. No mailbox provider publishes a number of days for domains.
If you kept using the mailbox for ordinary correspondence, your domain kept a history. Only the return to campaign volume needs care.
A break does not repair a bad reputation. Fix the cause first, then re-warm.
If you can plan the break, a small steady flow of mail through it is easier than rebuilding afterwards.

After a pause of a few days, no: carry on as before. After more than about a month of complete silence, yes, but not from zero. Restart well below your old volume and build back up over one to two weeks. No mailbox provider publishes the point at which a sending history goes stale; the 30-day mark comes from email service providers and their rules for dedicated IP addresses.

How long can a break be before it matters?

The answer depends on how long nothing at all was sent from the mailbox and its domain.

Silence	What to do	Where the line comes from
Up to a week	Carry on at your usual volume.	None of the provider documents cited here treats a short gap as a problem. Weekends and holidays are part of how any mailbox is used.
One to four weeks	Come back at about half your usual daily volume and return to it over a few days.	Caution, not a published rule. Your recent record is thin, and Google warns against sudden spikes.
More than 30 days	Re-warm: start low and rebuild over one to two weeks.	Twilio SendGrid, for dedicated IPs: “If you haven’t sent email messages through your IP address in more than 30 days, warm it up again.”
Several months, or a domain that never really sent	Treat it as new: a full warmup of two to four weeks.	Microsoft, on IPs that have not sent before: they “typically don’t have any reputation built up in our systems”.

What is documented, and what is not

The firm numbers come from companies that rent out dedicated IP addresses (all quotes here as of October 2026). Twilio SendGrid sets the 30-day rule quoted above. Amazon SES describes what keeps an IP warm once it is: “you should send around 1,000 emails every day to each email provider that you want to maintain a positive reputation with”.

These rules are about IP addresses that belong to one sender. If your mailbox is at Google Workspace or with a hosting company, you send from addresses shared with many other customers, and those stay busy without you. What goes quiet during your break is your domain.

For domains, the mailbox providers describe the principle and give no number:

Google, in its Top 10 Gmail sender issues: “Consistent sending volume is critical for your sending domain’s long-term email delivery success.”
Google, in its Email sender guidelines: “Avoid introducing sudden volume spikes if you do not have a history of sending large volumes.”
Yahoo, in its Sender Hub FAQ: “If you send emails at a certain rate and suddenly have a spike of activity, you could get flagged as a compromised sender and marked as spam.”
The M3AAWG Sender Best Common Practices, guidance from an industry anti-abuse working group (version 3.0, 2015): “Consistency of volume, whether high or low, plays an integral part in the determination of IP reputation and deliverability outcomes.”

None of them says after how many days Gmail, Outlook or Yahoo stop counting your earlier mail. Anyone who gives you an exact number of days for a domain is passing on experience, and that includes the table above.

The Yahoo sentence explains why the return is the risky moment, not the pause. A sender with no recent record that suddenly sends at volume looks like a hijacked account. The filter cannot tell that you were on holiday.

Three kinds of break

You paused a warmup tool, but kept writing emails

Then there was no break. The mailbox kept sending real mail to real people. Switch the tool back on or leave it off; nothing needs repairing.

You paused campaigns, but still used the mailbox

Your domain kept a history, at the level of your daily correspondence. The return needs care all the same: going from 15 personal emails a day to 300 campaign emails is the spike Google and Yahoo describe. Bring campaigns back in steps.

Everything was silent

Nobody wrote from the mailbox, or the domain only ever sent campaigns and those stopped. This is the case the table is about, and the one the steps below are for.

How to come back, step by step

Check that authentication still passes. Quiet months are when records break unnoticed: someone tidies up the DNS, a provider changes, a DKIM key is replaced. Send a message to a Gmail address you own, open it, choose Show original and look for three passes: SPF, DKIM and DMARC, the checks that show a message really comes from your domain.
```
Authentication-Results: mx.google.com;
       dkim=pass header.i=@example.com header.s=google header.b=Xk3fQ9aB;
       spf=pass (google.com: domain of anna@example.com designates
           209.85.220.41 as permitted sender) smtp.mailfrom=anna@example.com;
       dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=example.com
```
Start low. After more than a month of silence, begin where a first warmup begins, with a handful of emails a day. After a shorter break, begin at about half of what you used to send.
Write to people who know you first. Google’s wording is “a low sending volume to engaged users”. Customers, partners and colleagues who will answer are a better first audience than a cold list.
Grow in even steps. Google mentions “a common daily increase of 25% to 100%” for senders recovering from refused mail, and warns elsewhere against “immediately doubling” volume. Stay at the low end. At 25% a day, volume doubles about every three days, and an old level of 40 emails a day is back on day eight:
```
Day      1   2   3   4   5   6   7   8
Emails  10  13  16  20  24  31  38  48
```
Watch for refusals. A “delivery delayed” notice, or a code such as 421 4.7.28 from Gmail (“unusual rate of email”), means a provider wants you slower. Google’s instruction is to “reduce the sending volume until the SMTP error rate decreases. Then, increase slowly again.”
Hold, then add campaigns. Stay at your usual level for a few quiet days before you send to people who do not know you, and add those in steps as well.

A break does not clean a bad record

Resting a domain is sometimes suggested as a cure after spam problems. Google’s advice for senders with a high spam rate does include waiting, but as the second half of a sentence: “Avoid sending behaviors that contribute to a low reputation, and wait for the sending domain or IP address to recover from the low reputation.” The first half is what changes the outcome.

Recovery is slow by Google’s own account, in the sender guidelines: “It can take time for improvements in spam rate to reflect positively on spam classification.” If your break followed complaints, find and fix the cause first. Then re-warm as you would a new mailbox, and expect it to take longer than the table says.

Planned break? Keep one small boat sailing

If you know the quiet period is coming, because your business is seasonal or you are away for two months, the easier route is not to go fully silent. The M3AAWG sentence above says consistency counts “whether high or low”. A few emails a day are a volume.

This is a case a free warmup pool fits well. WarmupBay lets your mailbox exchange up to 10 short emails a day with other participants’ mailboxes, free and with no end date. With a badge in your website’s footer it is up to 30. Some of the emails get a reply, and warmup emails that land in spam are taken out again. Authenticated mail keeps leaving your mailbox while you send nothing yourself.

The dashboard shows where those emails landed (inbox, a Gmail tab, or spam) separately for Google and for other providers. When you come back, you can see whether your warmup emails still reach the inbox before you write to a customer. You can connect a mailbox before you leave, or on the day you return: a new WarmupBay warmup starts at 3 emails a day and adds one a day, which is the low start a re-warm needs.

What it does not do:

It does not guarantee the inbox, and no provider documents how it weighs mail exchanged in a pool against mail between people who know each other.
Ten or thirty emails a day keep a mailbox active. They do not hold a reputation for sending thousands.
It needs SPF, DKIM and DMARC in place. It checks them when you connect, and if they are still missing after 72 hours, the warmup stops.
Microsoft 365 and Outlook.com mailboxes cannot be connected yet. Gmail and Google Workspace work with an app password, other providers over IMAP and SMTP.
One mailbox per account, and the product is new: it launched in October 2026.

If the break ends with a fresh start on a new mailbox or a new domain, the first-time timeline is in How long does email warmup take?

Questions people ask

Does pausing a warmup tool for a weekend undo the progress?

Nothing in the provider documentation cited on this page suggests that. Mailboxes used by people go quiet on weekends and holidays all the time. The gaps that matter are counted in weeks, not days.

Do I have to warm up again after switching email provider?

Partly. Your domain's standing comes with you, provided the new provider signs your mail with DKIM for your domain; the M3AAWG sender practices say DKIM lets a sender “carry that reputation with them”. The servers are new to you, though, and Google's guidelines ask senders to increase changed traffic separately after significant changes to their sending infrastructure. Plan a short ramp of about a week.

Does an old domain that never sent email count as warmed up?

No. Age is not history. Microsoft says IP addresses that have not sent mail before typically have no reputation built up in its systems, and Google's sender FAQ defines a “new domain”, for its enforcement timeline, by what the domain has sent and not by when it was registered. A ten-year-old domain that only ever hosted a website starts where a new one starts.

Do newsletters sent through a platform need re-warming after a break too?

The platform's shared IP addresses stay busy through its other customers, so there is nothing to re-warm there. Your domain's own record still went quiet. Send the first issue to the subscribers who engaged most recently and widen the audience over the next sends. A mailbox warmup tool such as WarmupBay does not help with this: it warms a mailbox, not a newsletter platform's sending.

My business is seasonal. Do I need a warmup every year?

If the mailbox is silent for months between seasons, yes: treat each start as a re-warm and begin about two weeks before you need your full volume. The lighter alternative is not to go fully silent. Keep ordinary correspondence or a small warmup running through the off-season, so the record never empties.