Gentle Galoots,

One point about spar varnishes that may get overlooked:  Spar varnishes intended
for marine applications contain UV inhibitors to protect the finish against
ultraviolet light. The UV inhibitors "wear out" with exposure to sunlight.
That's why new varnish needs to be applied on a regular basis (to replace the UV
inhibitors). In the Puget Sound region, I get away with 2 coats every 2 years (I
keep my boat under cover when not in use). In Florida I'm told they need to
refresh varnish on boats every 6 months. Once a year is enough in most places.
YMMV.

For non-marine use it depends on how much sun exposure there is.

Chuck Taylor
north of Seattle
where we are getting some much-needed rain after a long, dry summer