[TowerTalk] TH-7 element insulators (plastics)

[Bob Alexander]

Howdy,
I finally got my TH7 off the tower for repairs following storm damage 
last spring.  The obvious damage has been taken care of and now I'm 
looking at the insulators.
The antenna has been up for just over 11 years in North Texas where we 
have 100+ days in summer and nights in the 20s with occasional ice and 
snow in winter.

All of the insulators (plastics) appear to be in good condition... they 
still have that slightly shiny "new" look.  No obvious cracks or chips 
.  Trap end caps appear as new.
VSWR curves recorded last spring before the storm damage were virtually 
the same  as those recorded 11 years ago.

Is there any evidence of sudden failure or these insulators after X 
number of years?  I realize climate is a major factor.

I know replacing all the plastics is the best choice but I want to 
avoid, if at all possible, the additional problems that presents at my QTH.

Thanks
73, Bob, W5AH