On Tuesday, April 25, 2017 at 11:06:03 PM UTC-4, Bojack J4 wrote:
How often should the mylar be redone on a horizontal stab/elevator?
The glider is always stored indoors in its trailer,and
everything looks fine with the factory installed tapes, etc.
There is sometimes a quiet air sound that changes pitch with elevator deflection especially when cold.

If you are starting to get noises you did not have before, and the bond of the seal to the stabilizer is good, it is likely to be time to replace the seals. Over time the seal material slowly loses the curve that is formed and made "stable" by heat. Likely it is the bottom seal making the noise as it is on the low pressure side.
A quick check of curve loss is to deflect the elevator(tail off the ship), and see where the seal stops having solid contact with the elevator. We just did this on a local ship and "new" noise went away.
Good luck
UH