Do I refinish windows with stain or varnish?

[driz]

I have some 17 year old Marvin wooden vinyl clad windows that are starting to show their age on the inner wooden parts. Nothing broken just the finish began looking thin and faded to the point where the condensation ect from our usual winters might start soaking into the wood so it;s time to do some PM . The bathroom window was the worst so I took it out and cleaned everything up with some bleach and sponge pad to clean up the bits of mold staining then wipe stained them. Both the casings and window frames look nearly perfect.
The question before I do the rest is whether I should just restain the rest like I did with the last one or stain then varnish them in the interest of moisture protection. It seems to me it is a lot easier to restain them every so many years rather than have to strip varnish or sand. What's the most sensible to you guys????

[driz]

Wow, I can't believe that nobody in the trades weighed in on this one.. Anyways, the wiping stain worked good for my fugly bathroom window . The wife went after the lesser worn ones with some tinted furniture polish and I have to say that it worked darned near as well. Any comments, yes, no, throw a rock through them anything.............>????????

[pushkins]

I see the advantages of stain with poly over it, mainly UV and moisture protection, however I see your point about it being much more difficult in future to refinish (having to sand etc...).
IMO and If it were me, I'd be doing the stain with polyurethane the advantages of the poly. to me outweigh the stain only. Polyurethane will protect the stain and more importantly the wood itself from the number one issue for wood....moisture. Stain alone when first applied is moisture resistant but within a very short time is simply a color not a protector.

To save time you can buy stain/polyurethane all in one.

If the windows are not effected by a lot of moisture then just stain would probably do, you will probably have to apply it more regularly than stain with poly. over the top.