For day to day use I generally grab anything that I am interested in and leave it seeding indefinitely, or until I need to prune to free up some space.
If I need to boost ratio I grab something that is new and hot to seed for a bit. In general though, I try to seed things that have lower seeder counts so that they remain available. Many times these are not things that I am really interested in.
If you are not using any private trackers then I suggest you get on one and just be active. If there is a particular thing you are interested in then there is probably a tracker for it.
I also seed Linux ISOs but those are public so it doesn’t help when it comes to ratio or anything. It’s just a thing that I do because I can.