Michael: I guarantee these are not what you first thought of.
When working on benchwork, or underlayout wiring, or schlepping things around, I find myself kneeling a lot. And my knees ain’t what they used to be. A $3 pair of foam knee pads is the best investment I can think of for making a model railroad.
Oh, they’re not perfect. The elastic strap might be a bit too tight for all-day use. They do sometimes slip down. These are solvable, especially if you’re willing to part with a little more $$$ and buy some of the flexible armor that a Knight of the Round Table would have been happy to have back in the day. But for $3, these foam pads work well for as often as I need them.
My first pair was purchased before the Saint Paul Bridge & Terminal was built. I recently was wondering why my knees hurt so much, even when I was using them. Well, foam wears out with use. Duh! No kidding. 14 years on one pair isn’t bad — probably should have been 13 1/2, but I’ll survive.
Sine qua non.
I wouldn’t even begin to build new railroad without these.