WD-40 does evaporate. I would not use it for a long term lubricant but it does have it's uses. Some of mine:
1) Removing duct tape residue
2) Rubber hose lubricant, epecially good if you are trying to slide a smaller size hose onto a larger nipple such as a 1/4" hose onto a 5/16" nipple.
3) removing electrical tape sticky residue from wiring
4) Removing road funk (tar, axle grease from semis) from paint
5) Cleaning poteniometers on radios. Say as if you have an old Montgomery Ward "Airline" stereo or ghetto blaster that cracks and pops when you adjust the volume or station.
6) I once used a can of it to get a campfire started in Wales.
Kano Penephite is the best long term lubricant I've used. It contains graphite.