I've found that every Pokemon player has a different strategy for how they play through the game. When I was younger, about 8, playing Fire Red on my Gameboy Advance, I wasn't a very strategic thinker- I didn't catch any Pokemon at all and barreled through the entire game with my Charmander. In fact I don't think I actually beat the game, I probably got stuck with a Gym Leader after realizing that I couldn't beat it without going back and catching pokemon, but I didn't really want to.

Now, playing Black, I'm very meticulous about keeping all six of my Pokemon on the exact same level. I'm about halfway through at the moment, and I've got a pretty solid plan worked out for whenever I reach the city. Using my starter Pokemon, I use it as my main weapon against random encounters up until I get to the city, and once I get there, I catch all of my other Pokemon up to it before battling the gym. Say my starter is at Level 24 by the time I get to the city, I would then get all of the other Pokemon leveled up to 24 before taking on the gym leader.