Hmm ... I've never deleted any of the 164 (or 162, or 152) mods that I've downloaded; they're small enough, and the idea of trying to connect to someone else's server is always there.
But ... by 21, I was down to just rotarycraft, dragon API, legacy craft, and cave control. Dyetrees and Geostrata I stopped fetching for use around 18 or 19, when he decided to change the focus of Dyetrees to be a magic mod instead of colored decorations and farmable dyes, and both myself and the people I play with decided that we liked underground biomes' stone generation better than Geostrata's "vanilla ore clump" style.
Will check that main forum thread and see if 22b came out yet.