I pretty regularly seem to lose all or most of my follows and followers, so I regularly scroll through my favorite posters' followers looking for those I've lost. I also make a point to follow everyone who follows me.
Discussion
Could be an issue with relays, especially if you switch between various clents frequently and they don't all use your same relay list. Snort.social has a nice feature that allows you to follow everyone that someone else is following. It's a good way to bootstrap a follow list, and then whittle it down from there as you see people in your feed that you don't want to see.
Iris allows that as well, but I prefer to be slightly choosier. However, I'm reevaluating that position.