In business communications, I believe it's common courtesy to respond to emails within 24 hours. If I get blown off, or if somebody takes 4 days to respond to my email, my impression is always that my counterparty views the matter as unimportant. For my part, if I reply late, and if the matter is genuinely important, I think it's proper and fitting to include a brief note of apology.

In email communications with friends, it varies. I'll often let conversations hang for a while until there's something new to discuss.

> In business communications, I believe it's common courtesy to respond to emails within 24 hours.

Different stroke for different folks, but I'm still very much in the paradigm where email is more like a letter in the mail, not like a text message, IM, or "please return my call" voicemail. [0]

Of course I recognize that email is often used for time-sensitive matters (like scheduling events), but any time I see an email that is likely to require multiple timely backs-and-forths I'll try to move the conversation to a more suitable medium.

[0] Here I'm referring to solicited emails sent by humans or transactional emails triggered directly by a human interaction. In practice our email inboxes also serve as a general "notifications hub" for all sorts of things including recurring events ("remember to pay your bill") and, of course, unsolicited junk.

Absolutely! The author doesn't mention what type of communication he means, but for business communications (in Belgium, where the author is from), anything over 24 hours (one working day) must have some explanation.

It's always better to explain yourself, otherwise, it looks unprofessional if you reply after a week as though it's normal.

Overall, the recommendations about email look very personal to the author and perhaps shouldn't be taken as general advice.

Different people and different work environments have different rules.'

I view my email once per week. If you need an immediate answer from me, I expect you to send me a slack/chat/pagerduty warning, even one that says "I sent you an email, I need answer by tomorrow".

Everyone thinks that their inquiries are urgent, top priority. That's not always the case, it maybe urgent to you, but not to the other person.

If something is critical, you can communicate via other means: phone calls, SMS, slack, etc.. and even then, there's no guarantee you will get a response.

In business context, I lean the other way, tend to give all parties as much leg room as possible.

I think The Eisenhower Method is a great fit for prioritization.

It's more like two business days in the academia, and only if a simple response is enough. Complex questions often take longer, because coming up with an answer may take an hour or two of uninterrupted time.

And if it's a cold email requesting something beyond a reply, and you don't have an existing business relationship with the sender, there is no expectation that you respond. An endless stream of requests from less reputable entities is an unavoidable fact of academic life. Such requests often go directly to the spam folder, as people have collectively decided that they are spam and trained the spam filters accordingly. Even if you think your request is legitimate, it can be indistinguishable from spam.

> In business communications, I believe it's common courtesy to respond to emails within 24 hours.

Sounds funny because I only read mails when someone tell me about them on MSTeams.

Between IM, supports tickets and jira stories I don't really see the point of emails anymore. If it is something that has an SLA tickets seem to be the way to go, if not Teams. If it is an urgent matter, mentioning my name or calling me will be a quicker way to go. Email seem to be in that weird place where some people still seem to want to insert invisible business matters in an ocean of junk and automatized mails/notifications you generally never subscribe yourself but ends up subscribed by default when given access to resources/applications.

>If I get blown off, or if somebody takes 4 days to respond to my email, my impression is always that my counterparty views the matter as unimportant

Usually it is unimportant, and the other side is just wasting their time.

You are conflating important with urgent. Something might be very important, but not urgent.

I might be slower to reply to something important because I need the time to get the reply right.

24 hours is ridiculous. I spent over 3 hours replying to emails yesterday and didn’t get through them all. And now I’m even more backed up on projects.

I think that for many cases that should be modified from 24 hours to by the end of the next business day. I feel no obligation to reply on a Sunday to someone who emails me on Saturday or late Friday. They can wait until Monday.

It's like everything else, it depends

If I ask a quote, get it, and answer only 2w later, I will probably apologize. If someone sends me a quote unprovoked, they shouldn't have any expectations of getting an answer, and if I answer even late, I won't apologize.

If my boss or people working on my project send me an email to get a status on something and it takes me a week to answer, I'll apologize- even if that's because I was busy on something more important. If a random colleague asks me for something unrelated with my direct responsibilities, similarly I'll get to it if I get to it when I get to it, and I dont think they should have expectations of receiving an answer, so I won't apologize

This must be why so many spammers now have automation set up to send me the first spam, then a second a day later asking if I got the first one, then a third to ask if I am still interested or willing to let their exciting opportunity to pass by. And then restarting the pattern in a month or so.

I am a site test engineer. I am also the primary contact for site test related questions internally for our factory and from customer and colleagues.

If your question needs a answer within 24 hours , give me a call and I will do my best to answer. If you send me an email, without any clear urgency, I will respond when I have time. Typically within a week.

My rule is: 2 business days if I know you, 2-4 business days if I don’t know you but you are offering something of actual value to me, up to infinity for everyone else. I only offer an apology for the first group.

This was previously true but no longer. Anyone who sends an email instead of a DM for something requiring a 24 hour turn around bears the responsibility for any resulting delay in 2026.

24 hours -> 1 business day

don't expect replies over weekends and holidays

Also Async doesn’t mean delayed forever.

i would suspect this flies over the OPs head.

It can be common courtesy as long as the other party is not feeling entitled to one's time and attention.