Slightly More Than Picayune Project!
When I moved into this rental house, it had a pretty decent amount of shelving already in the garage/shop. Alas, some of it was built in a very, uh, thrifty fashion.
This top shelf section, the shelf was made of 1970's style paneling. Thin and saggy. No way to run a railroad.

(And yeah, I need to tidy up my collection of special-tools-in-blow-molded-boxes, label them, too.)
Huzzah! New, thick plywood. What made this slightly more than picayune is that when I break out the circular saw, I start moving very slowly, trying to get precisely the dimensions I want. Careful set up, scrap of board for a fence, clamps, etc.
Also, I found a quick and dirty solution to my collection of rolls of Gates vacuum hose. (I decided a few years ago to never have to stop a project and go to the store for something this mundane.) They had been sitting on top of that tubing box, making access very fussy. I recently bought some half inch steel tubing for a project that it turns out didn't require it, so until I get another spare broomstick, this steel tubing plus one nail will keep them up out of my hair. Hmm, I might even mount it perpendicular to the joists, right up against their bottom edges.
(That steel gate handle on that floor joist? I have no idea. Just no idea. From before my time. I leave it there in case someday I can figure out that puzzler.)
Much better! Tomorrow, another saggy shelf just like it.