Duct Tape:

Duct tape is of course magnificent. But not all duct tape is created equal.

There is utility-grade-duct-tape, cheap by the roll, for short term fixes.

There is actual contractor grade duct tape, used for ... wait for it ... sealing air ducts. One assumes this is intended to be permanent.

Then there is gaffer tape, which is magnificent stuff, sticks to everything and itself, and designed to be removable without leaving a residue or removing paint. Used widely by musicians, roadies, film crews. Far superior to utility duct tape (and priced to match). I love this stuff, and shamelessly pester folks in the business for roll ends.

And, finally, there is Gorilla tape. It works. It is basically permanent. I carry a small roll (or half a roll) of the 1-inch variety in many kits. I fixed the rubbed-off lining in the heels of old hiking boots with this. Years and miles later, it is right where I put it. Wow.

Lubrication:

When WD-40 is not handy (e.g., when travelling), a tiny drop of automatic transmission fluid (ATF) from the dipstick of any vehicle is a remarkably effective penetrating solvent and lubricant. I'm scared to know what they put in that stuff, but it really works. Antique car enthusiasts put a squirt in the cylinders of ancient, seized engines that have been sitting for half a century and it seeps through the crud and corrosion like magic.