There is a lot to be said for consistency in how you carry, in that in an emergency you want to be able to react almost instinctively for the sake of speed. But at the same time, there are necessary variations in how one dresses for different occasions.
I use an IWB holster at about 3:30 or 4:00 with a cover garment about 95% of the time. I do have some other holsters for occasional use:
A tuckable holster worn in the same position when a cover garment isn't possible. In my own particular case, I frequently remove my jacket to don a robe before going to the piano at church on Sudays.
A pocket holster gets occasional use for walking the dog, getting the mail, or rarely a quick trip to the market - times when it just doesn't feel worth the trouble to put on a belt and IWB holster just for a couple of minutes.
A fanny pack holster, used primarily for long car trips, but occasionally when I am running around in shorts or a bathing suit. Yeah, I know it doesn't fool anybody who is looking for it, but not many people are looking for it. And in the car, there is hardly a better place for your pistol than right in your lap, and I don't really feel a need to impress people at rest stops with my sartorial elegance. So I find it a handy thing to own.
You mentioned small of back carry, and I have to add that having tried it out I am not a fan at all. In addition to taking a lot of concentrated practice to avoid sweeping yourself or others on the draw, it is also very easy to have your cover garment ride up without you knowing it, leaving the handgun to be freely observed and perhaps even grabbed. There is also some concern about falling on the firearm and severely injuring your back, although reports of that actually happening aren't prevalent.
