I have never really tended to stick with my starter, or with any one Pokemon, really. I like to keep trying to raise new Pokemon, try out different things, etc. I have a tendency to switch out my team completely about every third of the way through the game. I especially dislike keeping my starter around for too long, because it feels very cliche. I feel like I'm not being creative, not taking any chances or trying to figure things out, if I stick with my starter. I imagine that over half of the people do that, and I wanted to have to think a little harder.