I needed a bracket to hang a small fan controller off the side of a shelf in the rack. There are dozens for sale. None of them quite fit, all of them assumed a mounting hole pattern I didn't have, and every one was a week away and a fiver I'd rather not spend on something that was going to be wrong by two millimetres.
So I measured the thing with calipers, opened FreeCAD, and drew the bracket. This is the part that used to intimidate me and no longer does. A sketch on the back face, two holes for the screws I actually own, a chamfer so it doesn't dig into the shelf, and a 3mm wall because PLA at that thickness is plenty for holding up something that weighs nothing. The whole model took less time than reading reviews of the ones I could have bought.
Printed it flat on the bed so the layer lines run the right way for the load, no supports, twenty minutes at a draft profile because this isn't a presentation piece. It fit on the first try, which I'd love to claim as skill but is mostly down to measuring twice.
The thing I keep relearning: the value of a printer isn't the exotic prints. It's the boring custom parts that don't exist as products, the bracket that's exactly your shape, made the same afternoon you needed it. That's worth more than any benchy.