I used to stick hard to the no-oil rule everyone talks about. My potatoes and chicken would come out kinda tough and sad. Last week I tried a small brush of oil on some pork chops. They got way more crispy and stayed juicy inside. Now I do it for almost everything except maybe fries. It just works better, even if it goes against the grain. So yeah, I'm that guy adding oil now.
What's the deal with no-oil fries always turning out so bleak? I mean, @hugo_ellis, your fries crying for avocado spray is totally something I've seen. I tried that once and they were just dry and sad. Maybe it's just me but a little oil really helps them get crispy. Without it, they're basically just steamed potatoes, which is no fun.