Ok this is not only limited to the NDS games, I am actually playing Pokemon from the beginning starting from Yellow. How do I know which ones to catch early on in the game? Pokeballs are quite expensive and its not like I can make any money by defeating lots of wild pokemons. Or is it a case of whichever ones I want to? Do *all* pokemon evolve into something good? Do players generally spend a lot of time grinding to get the levels up or does a natural run through progress your levels sufficiently?