Back in my college days, I had a reloading bench in my living room. When the neighbor's bbq got away from him (@#$% drunk!!!) and spread to his fence and then his apartment, the security guard kicked in my front door to call the FD. They has a merry ol' time when the powder, primers, and loaded ammo lit off.
Storage space has been an issue, but that's changing. I've been keeping between 200 and 1k rounds per handgun caliber and 1-500 per rifle caliber on hand, but will increase by a factor of at least 5. I never get below enough to load out every gun and spare magazine - which is still more than I could carry if I need to bug out.
I tend to buy ammo every time I shoot, and buy more than I shoot. Then there's the reloading components...
I have also limited my chamberings, which simplifies ammo somewhat. .22LR, 9mm, .38/.357, .45acp, .223/5.56, .22-250, .308, 12ga and 20ga. I'd go much deeper if I were running wildcats or less common commercial loads.