Don't really have a philosophy of record cleaning, because I don't do it that much. If it were a philosophy, I suppose it would be "necessary force, but no more than necessary."
If a thrift record looks like it has stuff on it, but plays with fidelity and little discernible noise, I leave it alone. If it looks like it has stuff on it, and plays with more noise than I like, it is a candidate for cleaning. Once cleaned, they seem to stay clean on subsequent examination, excepting usual dust that can be brushed off. I can't imagine that new gunk has actually gotten into the grooves unless the record sleeve is full of gunk.
I can't really say I have heard any difference in the ones that already played well, the really dirty ones do get better after cleaning.
I do think that cleaning them is risky, the risk needs to be justified, and I would rather just listen to them. They are very tough, but I am not sure they are tough enough for multiple cleanings.
Most of the people who have heard my main big rig have listened to records from the thrift stores that have never been cleaned by me. No comments on noise or lack of fidelity.
On the second system with the Sony PS X70 turntable, I actually don't hear any more noise than I do on the main system.