How often do you "cheat" or grind?

It depends what we're doing at the time. I rarely test with accurately levelled characters because nothing I test is related to balance. I need to make sure that a new support gem X works correctly mechanically on a fireball in combination with with fork, pierce, GMP, and whatever else, so I make an item with the right links to do so, because playing normally until one drops is a complete waste of time, because I'm testing what the support gem does, not how long it takes to get the gear. I have a character on my local server at level 99 with all his points spent on skill points so he can use any gem/gear.

Once I know it works mechanically, it gets passed to Carl for balance. He'll use experience to judge rough starting values, and he and Rory will test it legitimately through various levels because they're testing for balance. Rory generally has a bunch of characters on the testing realm at various levels and with various builds.

High level balance testing (e.g. how hard is this map mod combination, etc) is usually done with characters made by you guys. Carl and Rory can copy characters from the default and hardcore ladders.

Most of us also play the game in our free time for fun, as well. I play with Rhys, my brother and a friend from my hometown most weeks on Wednesday evenings, and we don't have cheats on the beta realms.