This right here.
Case in point...my LPR West cam's glass lens cover has been coated with crap from my lawn sprinklers to the point that it has a quite fuzzy video. I have 'cleaned' it a number of times but it keeps coming back. Used vinegar, lemons, etc. but is no longer a clear image. I bought a new, replacement cam just before my daughter passed, but have yet to install it. Just don't have the energy yet. So right now, it is "good enough". If I go frame-by-frame I can usually pull out each digit of the plate if need be.
I agree with
@wittaj about the overview cams. Every cam position needs a plan based on what your purpose of that view is. If you want an overview that might show color of car or jacket, maybe make of car or number of doors, then get the proper cam for that. Just do not expect it to give you identify quality images.