Helpful Tip- Here's What I Use to Seal Exterior Cracks & Joints Around Doors and Windows.
One thing I've observed in doing exterior wood rot repairs is that the exterior-grade caulk used most often just doesn't last that long.
In a couple-three years it starts to harden, crack and pull away from the wood, letting in water at that point.
3M makes a product I've had a lot of success with. It's a paintable silicone.
Being silicone it doesn't dry out or crack over time. And being paintable it's, well, paintable.
It can be messy to use. What I'll do is apply a fairly heavy bead, then have a piece of cardboard on hand. I'll smooth down a small stretch of it, then wipe off the excess on the cardboard. This keep's it from getting all over the place. You'll need to use paint thinner to clean up, as it is silicone.
After it dries (the instructions indicate you can paint in 1/2 hour, which is nice) they recommend applying a exterior primer before painting. I do too.
The one peeve I have with 3M is they've changed the product packaging I think three times in the last year, kind of makes it hard to find.
It's more expensive than regular caulk, but how much does it cost to recaulk every few years?
Wishing you a happy and healthy home,