The thread locking product I use is LOCTITE
removable BLUE 242. The removable type is highly recommended when it is likely that a screw will have to be removed for any reason. To be honest, I would not dream of applying it to
all the screws in/on my camper.
If a screw just turns in the hole without actually tightening, I replace it with one having the next size up thread, e.g. #8 to replace a #6. It is often necessary to drill the hole in the held item bigger to let the replacement screw fit properly. If you don't, it gets irritating when the held item gets pulled outward as you try and tighten the new, fatter screw. Be careful when drilling the held item - it is not a good idea to slip through and drill also the hole that the screw threads into.
If the screw that just turns in the hole is part of decorative or sealing strip and nearby screws are tight, I would be inclined to remove the screw, plug the hole with clear silicone caulk and push the screw back in.
That's my two cents worth!
Luisa.
__________________