BobsYourUncle wrote:
Further to the good advice above, I would ask why they are coming out, and why they are stripped. That could be a red flag.
Pull a few right out and look at the threads. They should be clean and metal color.
But if they are blackened or rusty, you have a water leak problem. The screws are coming out because the wood is wet and rotting and no longer holds the screw.
If you do find rusty screws it might be a good idea to remove the entire trim strip and see why the water is getting in. There should be an effective sealant behind the entire strip. I have fixed the hole problem by forcing Bondo fiberglass in and redrilling after it is hard.