Hei, I made it a rule to never expose any wood to the elements. So I mark all my screws first, then I drill an oversized hole, fill that with thickened epoxy and then place the screw in the center of the hardened glue. I have no experience if this is really necessary and I am still building. So if you do this on a painted surface you will have lots of extra work. Like sanding and repainting. Above waterline this might be overkill. Peter
This is the best answer, but as mentioned ... it takes extra time. Perhaps worth it? That said, I have a skiff that I built back in the early 1990s that has fasteners for various pieces of hardware that are just as perfect now as they were in the beginning - I pre-drilled screw holes, ran a screw in/out to cut threads into the wood, and then used a syringe to pre-wet the hole just before putting the screws in. I used Sikaflex (can't remember which one ... a polysulfide I believe) in a small tube to just add a tiny donut of caulk around the shaft of the screw right under the head of the screw. Pretty quick. Screws don't come loose and it's all solid ... note that this boat's been stored in abusive conditions, mostly outdoors ... drains open, rain trying to fill the boat, bald sun 100F etc. It's painted with System III 2-part LPU and I can't say enough about how great and tough that paint is ... my only complaint is that it cures tissue-thin and doesn't hide any of my imperfections...
I believe LifeCaulk from .. Boat Caulk company (

) .. is the modern great caulk for this purpose. I'm using it for resealing windows in the canopy on my truck, but haven't started that project yet ...
Brian