When I was a kid we worked for a guy that did trail rides for city folks. Sometimes he would even let them bring their firearms along for the rides. One guy was riding and somehow his gun went off (Hit the horse and threw the rider.) accidentally while it was still in the holster. I do not remember the rig he was wearing or the gun he was carrying other than it was an old revolver. Apparently, when he went through the brush, he caught the hammer on some brush and cocked it, then while going through another bunch of saplings and brush, some how managed to have the trigger pulled. (He swore up and down that he neither carried the weapon cocked, nor did he touch the trigger.) If what he said was true, then he had a very unsafe holster.
1. A holster should be fitted to the gun it carries.
2. It should be fitted to the person carrying it.
3. It should be fit for the job you are doing. (When I am tossing hay bales, I want a holster with a flap, that will keep debris out of the holster and gun.)
4. It should fit the clothes you are wearing. Do not try to modify the holster you use for your belt when you are wearing sweat pants. Just use the dang belt or get another holster.
My .45 LC revolver holsters (Cowboy type) all have a hammer string on them to keep the gun in place. Can I quick draw with the string in place? No, but by golly when I am crawling through fences and brush looking for escaped goats and cows, I do not have to worry about it falling out.
When I am at the range, I use a simple slide in holster. It will be used only for storing and carrying the gun between shoots.
I do not CCW, so I am unqualified to respond on that aspect of it.
Inside Every Bright Idea Is The 50% Probability Of A Disaster Waiting To Happen.