If you find a face cleanser you like you don't need to switch away from it! Do you mean how many to use regularly? I have always used 2 different cleansers (one for the morning and one for the night), though I know a lot of people just use one. I have always liked using a more intense cleanser at night and a more mild one in the mornings. About twice a week I use an exfoliating scrub at night in place of my usual night time cleanser to clear off any dead skin cells, but that's just something I started doing recently.

In general, it's not good to be constantly switching cleansers and buying new ones. You should pick one or two that you like and keep and solid routine. Otherwise you won't really know whether one is working or not because you won't be giving it enough time to see the effects on your skin.

I have a handful of cleansers that are tried and tested and work well with my skin. I never really switch it up until I am done with the whole bottle and I pretty much just get which ever one comes on sale at the drugstore. I don't see a reason in switching unless it is not working for your. I stick with gentle cleansers for day and night.