The old coat of solid stain that has weathered makes a good prime coat if it's clean, dull & dry and is a sound coat, meaning not peeling or compromised in some other way. Duration is a house paint, whereas the other is a stain. The chief difference is the dry film thickness and sheen. the thin dry film makes the stain follow the contours of the wood and can give you a more authentic or maybe even rustic look, depending on the wood. It will almost always be flat, with no shine at all. The thicker coat will more fill in the grain of the wood and probably have an eggshell or higher shine, maybe even to a satin or semi-gloss. It most likely will not be available flat. A thinner coat means shorter life, the trade-off reflected in the price. A properly applied thicker coat of duration can be expected to last a good long while, but I wouldn't use anyone's "lifetime". If the wood has roughness or character to it, that you want to exploit for a certain look, I'd put stain on it. If the wood is smooth, almost shiny the way it is, I'd use house paint.

I found an absolutely perfect neutral grey I am IN LOVE with. I wasn't sure until swatching it. It is so wonderful. You can accent with warm golds or soft blues and silver. Its so versatile. It's called 'Light French Grey' by Sherwin Williams. We opted for 'super paint' in a satin sheen.

Well your home is going to be totally lovely! I like Dover White on a home exterior and in a shady spot. I used it just in the covered entry of my home and it looked so nice... It is just an all around good reliable color, in my opinion. The balance of my house was a more creamy white... and the way I got that color was to send a painter over to check out the color on a house a few streets over! My painter loved the Dover White and convinced a few of his other clients to use it. There's just something about that color...

I've been looking at high end roofing tile websites and one of them has a color expert that made recommendations for house paint colors with their orange/brown roof tiles. Here is a link to some of the schemes they recommend that may give you some inspiration: https://www.davinciroofscapes.com/blog/exterior-color-schemes-autumn/ You can color match to Sherwin Williams brand paint.