Loose powder poured into chambers with a flask was commonly used from the 1830's to the 1850's, the Walker was loaded with a flask and a loose Pickett bullet. By the time the Dragoons came out, the non-combustible cartridges which were basically a mini musket cartridge, were being sold or issued in the military setting, and also nitrate paper cartridges were firmly in use by the 1850's.
I'm sure Civilians, no doubt, used loose powder and balls/bullets and like was said they loaded them at home and just carried the gun . If a ranch hand or someone who carried a revolver for protection against dangerous animals, or bandits, or whatever didn't have access to packs of 6 Nitrated Cartridges I'm sure he'd have a flask, balls and caps in his saddle bag. Pretty much any hardware store etc would have carried combustible cartridge packs and people didn't shoot a lot, if you were just an average guy. So you loaded your gun and a few 6-packs of cartridges likely lasted a while. I imagine carrying loose components was rare by the 1850's.
Extra Cylinders were most highly likely hardly ever used unless, you bought a cased revolver that came with a fitted and numbered extra cylinder. I have seen original Pattersons and Navies with matching spare cylinders, so a gentleman out in the field could carry a loaded cylinder in a coat pocket. But this would be a very rare exception of a gun that was likely ordered like that and thus, extra $$ that most people aren't spending.
The majority of average people didn't even bother to carry a gun, didn't want to buy one, or just maybe had a revolver at home for defense. Little knockoff .31's and .36's besides Colts were available like Manhattans and they were loaded and just dropped in a pocket. Slingin lead out of a percussion hogleg was a rare occurrence , and even documented journal entries and letters home by Officers in the Civil War detailed that reloading their revolvers in combat wasn't common. The US and CS issued combustible paper cartridges in great numbers.
Carrying more than 1 gun was uncommon, in reality unless you were a Cavalryman issued a Brace of revolvers. These guys carrying 6 or more wheelguns likely did so in preparation for a raid, assault, battle etc I just don't see Joe Average walking around with a pair of revolvers. There was just no need, you'd probably get made fun of for carrying 2 guns like you were a wannabe Bill Hickok ............and it's extra weight and $$ spent to buy and carry a 2nd revolver to work on a ranch, walk around town or go to the store for supplies.
I don't see guys walking around with a pouch on their belt with flasks and balls , the flask pictured above is cool but not many like this were likely carried around.
I try to put myself in the period and think, what would a guy like me do in 1867 or something. I'd probably load my little Colt Pocket .31 with 5 balls and keep it in my pocket for taking my family to the theater, or going out to buy stuff. I wouldn't be carrying a flask and balls, like what am I really shooting at out there that would require a reload , entailing a pocket full of crap I'll never need as John Q Average going about my day
As much as we love percussion revolvers, it is plainly apparent what a giant leap the metallic cartridge was, and why anyone with even a remote chance of needing to fire a shot in anger got their hands on a cartridge revolver or had their hogleg converted as soon as possible. Being able to just dump 5 or 6 cartridges in a pocket for a quick reload is a huge thing. I can only imagine being a guy who carried guns for a living, like a professional Soldier, and turning in my 1860 Army and receiving an 1873 Model P.....it would be cutting edge technology to me. Just like the guys who gave up a pair of single shot pistols for a pair of Dragoons in the 1840s.
Percussion revolvers were used for such a relatively short period , and by the 1850's the rimfire cartridges were out, plus Pinfires were big in Europe. If not for the Rollin White patent, Colt, Remington and others would have been out of the percussion revolver business and into cartridge guns much sooner. So by the time the peak of percussion revolver tech was developed with guns like the 60 Army, 58 Remington, Starr DA, etc this technology was largely obsolete and people just used percussion revolvers out of necessity until the 1870's and beyond.
Percussion era went on longer than the 1870s.
The USA was awash in military surplus Cap and Ball Revolvers after the civil war. A used Colt 1860 Army could be purchased for something like $41 in todays money. I can’t remember the 1860s dollar figure.
The Colt SAA was not available for civilian sales until 1876. Also, It wasn’t until the mid 1870s that commercially available centerfire ammo was available. This stunted the sales of S&W cartridge revolvers to some degree.
From 1865 to about 1890 was a big transition era as cartridge guns replaced muzzle loaders and C&B revolvers. However, they were still quite common and common into the next century.
Black powder/ Percussion firearms were quite common in the Rural USA up to WW2. Yes, It was dying out. However you could still buy BP and caps. You still had people using them for hunting, self defense and plinking. Civilian black powder and percussion cap sales all but ceased during WW2.