... even though my deck is nearly 30 years old. About 8 years ago I did some repairs, strengthened steps, started systematically replacing nails with deck screws, and replaced two deck boards (the deck is normal pressure-treated).

Then I started the stain regimen, putting down two coats of the "one-coat" stain/sealant each time through. This deck is now effectively plasticized! Hey -- I've got a two-material "composite" deck now, made of equal parts wood and sealant!

Most recent coating was this past July, and presently it beads up all water just like the waxed hood of your car. Will probably bead up like that another six months. Next coating perhaps 2023.