This is the drawer — or pegboard, or shelf, or, if he's fully evolved, a small wall of labelled jars — that turns "I have to run to the hardware store" into "hold on, I think I've got one of those." The contents look unremarkable. The convenience is enormous.
WD-40 — and a Real Penetrating Oil
Two cans, side by side, because they are not the same thing. WD-40 is a water displacer and a light lubricant. A true penetrating oil — Kroil, PB Blaster, or similar — is what you reach for when a bolt has been outside for fifteen winters and won't move. Knowing the difference is half the magic.
White Lithium Grease
For door hinges, garage door rollers, latches, and any moving part that squeaks. A small can lasts years. The first time the back door stops creaking after twenty seconds of attention, you understand why the can is always there.
The Coffee Can of Mismatched Screws and Nails
A tin or jar — sometimes several — full of leftover hardware from past projects. It looks chaotic; it isn't. Every father-in-law has fished a perfectly sized drywall screw out of one at exactly the right moment, and the savings on small trips to the store add up over decades.
Drywall Anchors in Three Sizes
A small, medium, and heavy-duty anchor on hand at all times. Toggle anchors for the heavy stuff (mirrors, shelving, anything with weight); plastic expansion plugs for picture frames and curtain rods. Picking the right one is the difference between "it's been there for fifteen years" and "it fell down by Tuesday."
Three Rolls of Tape — Duct, Electrical, Painter's Blue
Each one solves problems the others can't. Duct tape for hauling and emergencies. Electrical tape for, well, anything electrical. Blue painter's tape for masking, labelling, marking spots on walls, and a hundred uses that have nothing to do with painting. All three live together.
Sandpaper in a Range of Grits
60-grit for stripping, 120 for shaping, 220 for finishing. A folder or sleeve in the workshop with a few sheets of each, plus some sponge sanders for tight curves. Sandpaper is one of those things you only realize you've run out of mid-project.