As resources and whatever provides a hero a bonus are so important in the first game, players that do not creep are at TBC Classic Gold a massive disadvantage. There's the more conventional RTS foundation and army building, then there is the dungeon crawl/RPG facet of combating and levelling your hero, and obtaining some extra resources to help with the foundation. Nailing this multitasking is one of the game's hardest aspects, but it is also why competitive Warcraft 3 is indeed exceptional.
If your hero is not involved in combat with another player, they need to continually be creeping. Remember, however, that once a hero buy WOW TBC Classic Gold reaches level five, they will no longer gain experience from battling creeps.