Bob,

What error did you make and what were the problems?

You got to the center of my question..... why do we need to
rebed/calk/seal every 4 years?

Is it possible do it once every 20 years if the "proper " product is
used?

In other words, it sounds as though you used 5200 in the past as a
selant and it failed. SO why did 5200 fail?

Chris