Good leather gear isn't disposable. If it's stitched, it can be restitched, whether it came from this workshop or someone else's.
Blown seams, worn thread, machine lockstitch that's let go; resewn by hand with saddle stitch that won't unravel again.
Pulled rivets, broken snaps, tired buckles and worn belt holes replaced with solid brass and copper hardware.
Dried-out, neglected leather cleaned, fed and brought back to working condition. Not everything can be saved. Send a photo and get an honest answer first.
Two or three times a year (more if it lives outdoors), work a small amount of leather conditioner or balm in with a soft cloth. If the leather looks dull or feels dry, it's thirsty. Avoid silicone sprays and anything that promises "waterproofing in one coat".
Rain won't kill good leather. Let it dry naturally at room temperature, then condition. Never dry leather on a heater, in a hot car or in direct sun. Heat is what cracks it.
Somewhere dry and ventilated, out of plastic bags. Sheaths: wipe blades before they go in, and don't store a knife in its sheath long-term; tannins and steel disagree over time.
Marks are the point. Leather that's seen ten years of real use should look like it. If something genuinely fails in normal use, get in touch. It can almost always be fixed.