It was when I started joining forums... there was probably not one particular situation that made me re-think my dog's diet, but the more topics I read regarding brands of food, the more it started to click.
We fed Molly Nutro Natural Choice her entire life... which is by no means the worst we could have done. I know for sure that I was a little more "nutrition savvy" about the time we got Lucy, because her breeder sent us home with some Iams and I immediately chucked it in the trash when we got home. My friend had given me a bunch of samples of Innova and California Natural, and I knew those were good brands. So this would've been almost 6 years ago.
It all came together when I finally convinced my mom to let me switch our cat's food.... I switched him from Iams, to California Natural. We saw a change for the better and that's when I was fully on board with paying attention to what I feed my pets.