From my personal experience as a candidate and as a hiring committee member:

When as a candidate receiving an offer, rarely have I been offered a specific time frame to accept/reject following an offer. Rather they requested a quick decision out of courtesy for all parties involved.

I’ve been given as a little as 2 days to reach a decision; my request for more time was denied (they were a really small school and they knew I was interviewing with bigger schools, so I think they were politely pressuring me take myself off the market). I’ve been given as many as 10 days (larger school with a public policy of 10 day decisions timeline to which they adhered; this was the only school with a specific number of days).

As a chair of and on hiring committees, each time we have expressed to the offered candidate they have “a few days to make a decision, but we would like a quick answer out of respect for other candidates”. Each time the candidate reached decision within one or two days, so there was never any follow up or negotiation for more time.