I used to book 1-3 month long trips when I was younger. Once I started working, all trips were usually 9-10 days because then I could get the most bang for my buck in terms of pairing vacation times and holidays and stuff.
My family also seems to really like booking for ten days.
I've realized though that the happy place for me is 2 or 3 days. Something like arrive in the evening, sleep, exploring day, sleep, chill day, sleep, then go home in the morning. I really can't handle much more than that anymore. Sometimes I'll even go home on the evening of the second day. I really like just enjoying the one exciting day and then knowing the day after that I'm close to going home.
If I do any longer than that I just get sick of the lack of routine. Actually, it's worse than just getting tired of it, I genuinely start feeling a bit mentally unwell. I get overwhelmed and I start missing the comforts of home like gaming and my familiar places.
Anyone else? :)