I once found a cast iron 12" in the trash behind my apartment. The only thing that was wrong with it is that someone had over heated it on an old bent burner and it had been warped ever so slightly. I only found this out when I purchased a glass top stove. The poor old pet was so dirty and scorched, I seasoned it just as Martha show on TV the day before I found it! I gave it to a friend who has a coil top and bought myself a nice Lodge. The next I got was a little 10" Wagner. Flat a die and so filthy, that the lady at the Garage Sale sold to me for 15¢! I took it home and scoured it and scraped it and boiled it for a whole day. Then I oiled it with Canola oil and popped it upside down in the oven for 1 1/2 hours @ 350ºF and turned off the oven and let it cool, gave it a good wipe and 15 years later I use it very often. No hot spots no scorches and above all no stick. After while you can use Sunlight soapy dishwater and a scrubby to loosen stuff and then just lick it with a bit of oil and wipe again.. don't leave any pooled oil in your pan. The best I've found is really hot water and a scrubber and that usually cleans it up.
Recently, I have learned from America's Test Kitchen that we are cooking too hot in our pans. Even browning should be Medium to Medium High. And Braising should be Medium Low. But I have found a way to roast a chick fast and deliciously, Heat oven and 12" Skillet to 450ºF and plunk your S/P and Oiled Chick on the hot,then roast at 450ºF for 35 mins, then turn off the oven and let the Chick roast for another 35 mins. Result a beastly mess in your oven, but a perfectly roasted chicken and Crispy skin. (See America's Test Kitchen: Recipes>Week Night Roast Chicken. Makes beautiful gravy and nothing is scorched or burned!