Analog: The question about cleaning is based solely on chemistry. Black Powder, and the ascorbic acid that is the base of the substitute powders, contain chemicals that become very corrosive acids when combined with air and water- moisture from the air. Those acids eat steel. So we clean after ahooting.
Cleaning after each shot is based on how the gun performs. Each gun is different. The objective is to know where exactly that next shot is going to hit a target( animal) when you fire the gun. To do that, most find its better if they clean after each shot, so they are firing a cleaned gun. Others get away with shooting several shots before cleaning. The danger in not cleaning is weather related, so there can be no standard advise on this. Some barrels in some weather conditions are going to foul faster than other barrels in other weather conditions. The question for you, how do you know what your barrel is going to do( foul) until you find out that you can't seat that next ball or bullet down on the powder? Then its too late. You have a ball stuck half way down the barrel, and you either have to pull it out, then clean, or pour water, or cleaning fluid down the barrel to soak the patch, which in turn will probably soak the powder charge, so it won't fire, or will only burn partly making the ball go about half way to the target! Either way, you will need to pull the load, or shoot it out, then clean. So, why not clean each shot, accept the challenge of shooting a single shot, Muzzle Loading firearm that it is, and do it right? If you just want to challenge yourself as a hunter by shooting a single shot rifle, there are plenty of butt-stuffers made in single shot actions. You can just load one cartridge in your gun, instead of filling a magazine with ammo, for that matter.
So, ultimately, it comes down to asking yourself why you are shooting muzzle loaders in the first place. That is our traditionalists argument with the folks who want to shoot those new In-#@@#$ things, we don't talk about here, too. If you only are gitting into ML shooting so you can have a few more days to hunt deer in a " NL season ", in your state, that is a poor excuse for going to that trouble, and expense. That is why we don't talk about those guns here, and why we really don't care too much when clerks in gun stores that no longer carry any black powder, or supplies for traditional ML guns, tell these customers they don't have to clean the guns like traditional shooters do, they can use premeasured pellets rather than take the time to work up a load with loose powder, they can shoot modern pistol bullets in these plastic sleeves, and same all the dirt and trouble that comes if you use lead and cloth patches, and you can kill game out to 250 yds with these new fandangled firearms. Those guns will be rusting out within 2 years, the owners will be having trouble getting the gun to fire using anything, the bullets won't magically hit their target at those long ranges, and those pre-measured pellets may just NOT be the most accurate load for that gun, afterall. The gun goes into the junk pile, the owner goes back to shooting modern weapons, and the ML only season will eventually be left to those of us who continue to shoot traditional firearms, take the time to clean and load them properly, and like the race between the tortoise and the rabbit, the tortoise will win the race. Traditional guns have come and gone in waves over the past century, and I am sure they will come back again. Just the problems we hear about some of the new guns, from shooters using substitute powders convinces me that its only a matter of time when younger shooters will wise up, reject these guns, and go back to shooting traditional firearms. What we have to do is continue to hold our hands out in friendship, and be prepared to teach them how we do things. And, maybe as a group, find a way to make Black Powder more easy to acquire.