You are probably burning up your grinders because you want to get it done now. Stainless with the chrome and nickel in it creates a heat source and hardness which makes it harder to grind down stainless.
The better the wheel you use, the longer the grinder will last.
Your not wrong, I do want to get it done now or better still yesterday but let me clarify. Most of my grinding is in a foundry setting. I may grind 6+ hours a day on gates and risers and I hate grinding. It is noisy dirty, dirty,dangerous and I've been doing it for too long. Much of what I grind is chrome carbide iron which is very hard and work hardens as you go. Occasionally a 6" diameter riser that I first have to cut with an abrasive cut off disc(which is really hard on the grinder) and then grind down a 1/2" of riser. My collection of burnt out/destroyed grinders is from 35+ years of doing this and they don't owe me anything and yes, the right abrasive is really, really important.---Meltedmetal