We gain levels fast, about every other week. It's becasue we have 2 players so more XP for each, we get more things done and it goes faster with just the two and I don't treat the party like they are 2 PCs. I'd run the game with the same encounter if there were 2 PCs or 6. We game for about 6 hours a week, I do reward XP for role playing and other non traditional awards.