I am curious about your experiences doing the in between of a fully prepared campaign and just running something on the fly. Do you do much whipping up your own content preparing for a session? Is it just too much work to prep? Poor tools? Can't find good maps to download and integrate?
I can only speak for myself, but when I'm planning for a session I regularly just figure out how many combat encounters I want and usually figure out an extra couple.
Then the story just takes people where it takes them. Maybe I thought they were going to investigate the mansion but instead they head to the swamps. Maybe they attract too much attention in the wrong part of town and get jumped in an alley.
So I may (or may not, I'm lazy) have done a quick sketch of the mansion but all I did for the swamp was think what kind of threat could be there. The alley thing was just made up on the fly but I can either grab appropriate NPCs or those bugbears suddenly become humans and part of the Red Mask gang that I just invented.
I do a lot of theater of the mind until initiative is rolled. With a mat, it's easy to just draw some lines and we're good to go in whatever setting I envision at the moment.
Part of it is probably just that because I can have pretty maps I feel like I should. But even simple maps simply take more time.