I have a basket with about 15-20 toys of various shapes, textures, colors, and sizes. I keep about 5 to 8 out at a time, the rest remain in the hidden basket (in a cupboard over the fridge).
I know that cats get acclimated to toys, and will begin to ignore them (Hmph! I've already killed that thing eleventy hundred times.) With no real set schedule, every couple weeks I go around, find all the toys that went under appliances and chairs, gather up all the other toys, and put them in the basket. Then I put out other toys. My cat has been with me only a few months so far, so each rotation introduces at least one new toy, but also brings back some familiar ones. As toys wear out, I will trash them and buy new.
The cat seems to okay with this, and plays with his toys with equal vigor no matter how long they've been out. At least, he hasn't complained so far.
I wonder about the long-term effectiveness of this (lack of a) plan. Should I have more or fewer toys at a time? Should I get the rotation on any schedule, and if so, how often?
Searches for "rotate cat toys" are all ads for cat toys that rotate, and "switch/ change cat toys" are about switching to different kinds of food or litter.