Long ago, when I was just a teen who had forgotten to turn on the oven to start dinner, I thought maybe I could make up for lost time by turning the temperature up as high as it would go. Why did the oven have a setting for 550°, after all?
I learned the hard way that bumping the temperature half again as high does not make the food cook half again as fast. What it does is make the outside of the food cook way too fast while the inside never even gets touched by the heat. In other words, you end up with something burned on the outside, raw (maybe even still cold) on the inside.
As for why the oven control goes all the way up to 550°, I’ve learned there are very few times you actually need it to. The most common is in roasting meat, and even then it’s optional, and you turn it down to 350° as soon as you put the meat in. This is supposed to give it a crisp, browned outside before the falling temperature settles down to cooking the roast through. I say “supposed to” because I haven’t done it often enough to say whether it works. There’s usually something I’m cooking along with the meat, like baked potatoes, that needs to cook at an even temperature all along. For browning the outside of the meat, there’s always the broiler.
Most of the time, 350° is the temperature you need. It’s certainly the best for baking cakes; if anything, you should go a little lower, like 325°. There are exceptions; biscuits and rolls often call for 400° to 450°. But you’ll find they cook just fine at 350°, though they may not brown so perfectly. Just increase the cooking time by a few minutes and be sure not to take them out till they test done. Baked potatoes are also supposed to cook at a fairly high temperature but will be fine at 350° if you give them about an hour.
We’re fortunate to be able to measure oven temperatures exactly. From what I’ve read, home cooks in times past spent a lot of time figuring out if their ovens were hot enough by sticking their hands in and counting the seconds till they had to pull them out — or, less painfully, putting in cubes of bread and watching how long it took them to brown. Turning a dial to a number is nothing compared to that; let’s make sure it’s the right number.