In Red, I just used my starter for my first run, then built a six-member team for my subsequent play through. In Gold, my team consisted of 5 Pokemon. I didn't want to ever have to put any of my Pokemon in the PC, and I wanted space for Cut/Strength/Flash/Whirlpool/Waterfall/Rock Smash users and Pokemon I wanted to level up and evolve, so I left a slot open. I did train a few additional Pokemon to use, but I never counted them in my team.
In newer games, with the advent of the revised Exp Share, I use a rotating team of more than six members. As a result, I don't really have a "team" in the same way that I did in earlier games.