I have no idea what your gun wrench is talking about D/D? I personally have 3 sets lurking around the Sdog casa, two of the 3 are 10 years old, one is about 7 YOA. The only thing I did differently than factory instructed on the front Tritium insert, was to use Loctite bearing and sleeve retainer, rather than the factory suggested type of Loctite. Probably twice a year, I wick another small drop along the seam of the insert. Haven't lost one yet! As to the rears, I'm really confused? Have never had an issue of any kind there? But, they're getting a bit dimmer than when new, after 10+ years. So it's time to buy another few sets and slam them in.