I'm relatively quick to follow someone, 1-2 interesting posts is usually enough, but then I evaluate the posts over time, usually weeks, before I decide if I'm keeping them.
I view following as deciding what I want to see in my feed. I know there is a mute option, but it seems pretty rude to follow someone and then mute them. "Sure, we can have dinner, but please dont talk to me since I don't want to hear from you."