Actually this is an interesting question.
The whole notion of "in rotation" is a bit foreign to me. When I buy new records, I guess you's say they stay in rotation until I have a firm grip on the music, then they go on the walls.
Later I'll get an "enthusiasm" such as listening to a specific composer or a specific artist or conductor and then I'll drag out all of their stuff that I've got in my collection and start playing through until the enthusiasm wears off, or a new one comes. Sometimes the enthusiasm is driven by a recent live performance, or a new acquisition. But frankly, I rarely repeat an LP in a year.
I mean, listening to records 3-4 hours a day, how many records can you really listen to? Let's say I listen 6 days a week, 6 records per day. So that's maybe 1500 or so unique records in a year, since I'm traveling some too. My collection is only 3,000 or so, so I guess I'm listening to about half of it, but I'll bet there's stuff there I have not heard in 10 years or more.
thanks for asking. Fun to think about!