My dynasty league expands during the postseason and then lowers after preseason week 3. Any tips on who to look at for dropping?
Drop the guys who you think have the least value on your team.
To expand on @morestagedives comment, rank your guys (based on value in-season or startup value) in a list outside on your league platform. I find actually writing the names on paper or even in a Google doc helps a lot. Separate players by position first. Than combine positions and rank all players.
This should help you identify the bottom of your roster.
Once you have those 2-5 players, research their ADP and any current hype. The worst is when you drop what you think is a “roster clogger” and they are picked up immediately.