I used to but one day as a kid I realize why do I need to stick to this starter? Kinda of an eye opener. So chances are I box'ed them after playing though the game once. I Kept pikachu,totadile, probably blazeken. Didn't like the last 2 gens.
I rarely release or permanently box my starters for the reason that my first Pokémon in each game is essentially my companion; I have them always by my side. I even remember my first starter, Wildfire the Charizard - Until my Red version's cart battery died. Rest in peace, old friend.