Depends on which off-body method you use, too. I've always hated having anything in my pockets pulling downwards on my pants, so early on I went to a backpack for every-day carry. It's grown over the years, reaching a current weight of 32lbs. By now, 25 years later, I'm far more likely to forget to put on pants (it only happened once, but my friends will never let me forget, heh) before walking out the door than I am to forget my backpack. Pants don't weigh much, but anybody will notice how light on their feet suddenly losing 32 pounds makes them. If I don't have my backpack, I also am without my wallet, keys and phone, so remembering any of those causes me to remember the pack as well.
I've often thought about modifying it to conceal a pistol for a behind-the-back draw. The mod would be reasonably secure, since it would be hidden by my body while wearing the pack, and there's no reason I couldn't use a retention holster as well, secured inside the hidden pocket.