Ironman only. What's the point otherwise?
Only then can you look at your empires, achievements and victories with pride, otherwise you know you cheated.
If I can't be arsed to think thru the ramifications of a decision and it blows up in my face, then I deserve to lose, or waste 30 years rectifying mistakes. Isn't part of the fun being in jepoardy and digging yourself out of it? Is it fun to coast to victory all the time?
Where's the fun in going back to earlier saves, and avoiding all the errors? You're just cheating yourself.
IRONMAN!