For me it usually takes me 1-5 days max. The only time I didn’t get to a review right away was because I had family visiting upon our return, other than that I like to get it taken care of right away. On the flip side it has taken sometimes a few days to get feedback from sitters and other times it has taken nearly a month.
When it took a really long time for us to get feedback I just politely messaged the sitter and asked if they had a good time? Anything we could improve for future sits? and if they would write us feedback soon thereafter they did. Sometimes people just get super swept up with life so I try to remain flexible and not dwell on it.
This has been discussed quite a bit here on the forum. Here are some other discussions regarding reviews and feedback and some cross-over with your question. I hope this helps!
Here are some topic threads to have a look at, feel free to use the spyglass to find others: