That would be the main reason I grow my own. I know what is in it. If I was able to buy high quality bud that did exactly what I need, I would reconsider growing, but since I can't, here I am. The local here is selling what one stoner friend of mine says is good stuff for $125 Cdn/ounce. At that price, buying the stuff would be cheaper as well as a lot less work. However, my trials of dispensary weed have all been expensive disappointments. The commercial guys just don't seem to get it.
Another stoner friend of mine gave me a bud from his supplier's grow of Big Bud. It was ok, but unremarkable. Whatever, I broke off another piece to grind up, and to my shock, the inside of that bud was rotten before dried. How in hell my friend managed to not notice is a bit of a puzzle to me. I debated whether to tell him, but decided not to bother. Knowing him a bit, there is zero chance that he would toss the stuff if it did the job for him, and I doubt that his supplier would have admitted what was up with the bud.
Homegrown for me, period.