Depends on what I'm cooking, but always for chicken breasts. Roasting at a high temperature works great (it's not the only way), but can mean the overcooking time is pretty small. It's an easy way to respect the bird and get the best results possible.
Thighs on the other hand, I just go by eye, you really have to try hard to overcook those.
Might be worth noting that using a thermometer well does require some amount of skill and experience, you need to insert it into the right location for the data to be repeatable. Easier to learn than cooking by eye, though.
We dressed like this in the 80s and 90s, too, and still do. Despite all the various fashion movements over time, my experience is that most people dress like this most of the time. The fashion of simple comfortable clothing changes very slowly.