I agree that discussing session length with a new T from the start is a good idea. My T does 50-minute sessions, though going a couple minutes (like 3-5, not 20) over on occasion tends to be OK (like if I'm upset). But I also know of T's who do 45 minutes and others who do a full 60 minutes. Or my ex-MC, who technically did 45-minute sessions, but we were generally there for an hour, sometimes longer (and he did the same with other clients, so was generally running late).

I think it's good to check on other policies right in the beginning, too, to avoid possible conflict or confusion later. Like what kind of outside contact is allowed and under what circumstances. Whether you can request an extra session. Whether you can reach out to the T in crisis--like will they answer their phone at any hour, including the middle of the night (ex-MC), will only check/answer during office hours (some T's), or something in between (my T)? And anything else you're wondering about. Like vaccination status.