I'm down right neglectful of maintenance on my pellet grills, so far. it hasn't really lead to any real problems for me.
My auger did stop working on my GMG Davy Crockett recently, I don't know exactly the cause yet, because it's been too cold , and I have other pellet grills I can use. I do need to look into this, because I really love the Davy Crockett for small cooks, like a single rib roast, or tri-tip... It's actually darn near my favorite pellet grill... basically if it fits , I will use the Davy Crockett. How much I use it, might have something to do with the failed auger situation.
Without knowing for sure what went wrong with my Davy Crockett... I can tell you that I've never had a auger tube jam in any of the other 5 pellet grills I own. I've seen posts and such from others, who report having pellets get damp, which then expand, and then can potentially fully lock up a pellet grill's auger tube. Presumably the man way to avoid this, is to make sure you don't get moisture in your pellet hopper and/or the auger tube.
I scrape my drip trays off as needed... I try to keep the grease bucket from overflowing... I do occasionally run my pellet hopper down to empty, and clear out any 'dust' that might be down near the bottom... ( running it out is sometimes done accidentally though. ).
Anyway, i don't have any major pearls of wisdom on maintenance , but would love to hear some. ( but I'll probably just ignore them and go back to being more or less neglectful of maintenance )