How Long Can An Airplane Sit?

Bill,
The citabria I bought last year had been serviced regularly with exxon
elite semi-synthetic oil. I've continued using this product. According
to exxon, I'm a very smart guy Whether it really works or not remains
to be seen but even exxon recommends changing the oil before extended
periods of downtime and having a sample tested for water content every
60 days. I haven't had that done but I think I will. Check out their
admittedly biased website, exxonelite.com.
Dave
68 7ECA

Bill Denton wrote:
A pilot owns an airplane.

He isn't able to fly the plane very often, but when he does it's usually two
hours out for a $100 hamburger, then two hours back.

The airplane is always hangered; all inspections and maintenance are done by
the book.

How long could the airplane sit between flights before it begins to
deteriorate?