It's a bit complicated. I have some longstanding favourites I play every on PC now and then, somewhat regardless of whether I might have any other games in progress on PC. I can also have some more finishable games I play, in which case these longstanding favourites might temporarily take a step back or not. This is all for myself; my partner also likes watching me play but only on consoles, where I might have some finishable games I play kind of alongside the PC games. But I might also play some games with my partner on PC every now and then. It's a bit of a mess, but it works for me.
I absolutely do not ever start a new finishable game in a certain 'slot' if I'm already (actively) working on some other game in that 'slot'. I guess the 'slots' are really PC and consoles, so just two, i.e. I'm actively working on only one finishable PC game at a time and one finishable console game at at time (or just one of them), because I play them in different situations. Of course sometimes I kind of drift away from finishable games I've started, in which case I might start new finishable games at some point, although I have some reluctance to do so.
See, there's a bit of a system here, but it's somewhat complicated. It's not too orderly, and it's not pure chaos either - it's a nice blend of both (just like me on many things in general, which kind of makes me appear a conflicted person to the outside sometimes).
