Cheats for Heroes 4.

Using codes is pointless; it makes the game less interesting, unless you're a complete newbie. I used codes when I was starting out, even on the beginner difficulty. Once you learn how to play, even at the apprentice or master level, codes become uninteresting.

IMHO: In offline tournaments, codes are essential for initial map exploration, especially when time is limited. It's frustrating to spend several hours on a difficult battle (without codes) only to find out that it wasn't necessary for a successful playthrough.
The main thing is not to use codes during the final playthrough :D