I am not a champion shooter and I'm not giving advice. Just adding a note regarding what I do.
When I was shooting the monthly matches with our local club, the typical match involved five relays of five shots each, for a total of twenty-five rounds. I made it my practice to swab the bore between relays, i.e. after every five shots. I used a patch wet but not dripping, followed by a dry patch. I would save the dry patch (okay... I'm a cheapskate...) and saturate it after the next relay to use for the wet patch, followed by a clean, dry one to repeat the procedure.
I like T/C #13 blackpowder solvent. I have tried a few others, including plain water, but old #13 works. I don't produce enough saliva for "spit patches." I've tried that, but my mouth is too dry.
Just shooting for fun, I swab when it gets hard to load. Depending on the rifle, this may be after every other shot, or it maybe not at all. The ideal load is one that is accurate, easy to seat, and doesn't require much swabbing. In my opinion, the right type and amount of lube is a critical factor in this. Lots of lube that keeps fouling soft and fluffy rather than hard and crusty is the secret, I believe.
I recently pulled out and browsed through my copy of Walter Cline's book, The Muzzle-Loading Rifle, Then and Now. This is a classic. Mr. Cline was an absolute fanatic for accuracy, and he devoted something like a full page to a description of proper bore-wiping technique. In shooting for best accuracy, I believe he advocated wiping after every shot. One thing I had forgotten was that he also described using an over-powder wad of felt. I had coincidentally tried this, for the first time, in my last trip to the range. I found that the felt wad, saturated with grease, made loading easier, protected the patch from getting burnt, and eliminated the need to wipe between shots. I don't know if the wad helped in the accuracy department, but it sure didn't hurt. So, the old dog learned a new (to him) trick.
You've gotten lots of good input from the forum. Not everyone agrees with everyone else, but the bottom line is that you have a lot of options to try so you can determine the best practice to employ for your rifle and your style of shooting. Good luck, and have some fun with it!
Notchy Bob