Cast Iron Skillets

57 years old, and eaten from/cooked in cast iron all my life.
1) There is no sin in soap. If you can taste it, you didn't rinse well enough. Period. I've soaked them overnight or longer in soapy water, scrubbed with all sorts of soaps, and they power on. Not sure where this soap fear comes from. Mom did the same with the Dutch oven I've now inherited in which she did the Sunday roast for 70 years.
2) I'm currently using a pan I found in the woods 30+ years ago rusted to a fare-thee-well. A general scraping with a metal scrubber and Several grits of steel wool took the rust off. Coated the whole thing with oil and put in a very slow oven for hours and it was good to go.
3). I fry an egg in cast iron nearly every day and need to use less than 1/4 teaspoon of butter.

Lodge is just fine, but I agree with others: new pans just aren't smooth as older pans. My newer one sticks like the dickens.

I have a few cast iron griddles (a flat one, a ridged one and one of the big rectangular ones with a flat side and a ridged side). I have them because they are big slabs of metal that don't warp over high heat and don't get damaged with rough treatment, unlike non-stick and aluminium pans, which can't stand up to proper searing or flatbread-cooking temperatures.

I'm not precious with my griddles. I keep them dry. I keep them greased. I don't shock them (by putting cold water on when they're hot) or soak them. If, despite my efforts, rust appears, I don't sweat it, I just scour it off, dry the pan by heating over a low flame, and re-grease. I just use vegetable oil for greasing. I don't worry about soap.

I may not have a beautiful mirror finish on my pans 50 years from now, but they do what I want them to do. I don't expect to be able to cook eggs or fish on them without added fat, but I don't want my eggs or fish without added fat anyway. So I'm happy.

I also have an enamelled cast iron Dutch oven. Enamelled cast iron is a bit of a diva, and I am precious about that, as it is easy to damage. If you want a rough-and-tumble pan, stay away from enamelled cast iron.

Tips for cooking with cast iron are:

Always let it heat up slowly over medium-low heat (otherwise you'll get hot spots and uneven cooking); the flip side of this is you can turn the heat off five minutes before the end of cooking and it will keep merrily cooking your food by its residual heat. This trick means it makes an amazing food warmer for the dinner table or buffets!

ALWAYS use an oven glove or a good handle cover, and make sure others know never to touch it with bare hands unless they know it is cold - hot cast iron will take your skin off.

And find somewhere to keep it that its weight won't discourage you from using it. I keep my griddles on the stove top and the Dutch oven on the kitchen counter - if they were in a low cupboard, I'd never bother to haul them out!