I only preheat the oven when I’m making baked goods (cakes, cookies, etc). But for other stuff like frozen food, meats, vegetables, etc., I just put the food in when I turn the oven on. I use the recommended cooking time as an initial estimate but will test the food to determine actual doneness. Is there any disadvantage to doing that? Are there taste-related benefits to preheating the oven?
Not that I’ve ever noticed–preheating always seems like a waste of energy to me.