I don't follow everyone who requests as I want to keep the number of contacts that I follow manageable (200 max) as I like to enjoy others great photography.
I don't collect 'favs" but I do expect a fav or comment every once in a while as it tells me that that my contact has an interest in my photography.
I do 'clean up' my contacts from time to time as some drop out of action or do not seem to follow my posts.