Well, I bought a cast iron skillet about 40 years ago at a local department store (remember them?). Can't remember seasoning it, but probably did way back in the day. I just wash it out with hot water and a bit of liquid soap and a scourer to remove the occasional bits. As good as teflon, cheaper and less poisonous. My favourite pan. I think the main thing is to use it a lot, and don't overclean it. The type of oil seems not to have mattered much, but it's mainly olive, sunflower or rapeseed. As always YMMV.