I mounted a key cabinet on the wall. Nothing fancy, bought it at Home Depot. I put the master key for each item or location (workshop, house, garage, etc.) on a separate tag in the box, labeled by item. Same for spare vehicle keys. I key alike where possible, for example, one key unlocks every door on my house, another the shop, a third the garage. I use the same padlock for almost everything, the exceptions being my fuel oil storage tank and box trailer. Fuel is too valuable to trust to a commonly available Master key code, and the trailer gets parked in some nasty spots, so it needs beefier locks on the doors and anti-theft cables.
My wife and I each carry a ring with the keys to our primary vehicle on one end of a quick disconnect and keys for the house, shop, key cabinet, and the common master padlock on the other end. We have garage door openers, so no key needed there. My ring has an extra male quick disconnect which I use whenever I tow a trailer. I group sets of keys by trailer on a ring in the key cabinet, so I can just grab, hook and go. Each personal keyring has a carabiner. I keep mine on a belt loop, my wife hooks hers inside her purse.
I also have a work truck, and a remote office and storage cage I rarely visit. Both sets of keys for the truck are kept in the cabinet. One set has a carabiner, the other is a spare. On the set I carry, I keep the office and storage cage keys, plus a set of gate keys for various other work facilities, and a spare quick disconnect so I can take my house/shop keys. Work has their shit together, there are four gate keys for the entire nation, and the facilities themselves all use an access system that allows security to track the comings and goings of employees and contractors.
Any time I go anywhere, I carry less than a dozen keys at most, and often no more than half of that.
