I've heard 4-8 years (give or take a few) depending on the brand. I'm not quite sure why they go dim, probably has something to do with the half-life of the chemical in them.
I just replaced the factory NS on a G19 that was purchased new in 1994.... the NS were dim you couldnt see them during the daytime but they still glowed at night.
I probably wouldnt have replaced them then I compared them to a few other pistols w/ NS that I had and realized just how dim they really were....
I cant imagine light causing something that is radioactive to decay faster.
I use to have a Sig 220SS with trijicons on it. Not sure how old they were (not the original buyer of the gun, bought used). After around4 or 5 yrs of owning the gun, one day I went to get it out at night and noticed the front sight out and the right rear dot out. The left rear dot was nice and bright.
Looking to get a Ruger LC9... however, I never noticed they do not have night sights... Just got a Sig Saur and the sig night sights are awesome. What options are there for the Ruger LC9?
What factors contribute to good or bad night sights? What effects their life? Obviously those who spend top dollar would like to think their decision is the best, but does that insure it?
Ive had a few on diffrent glocks when i was working out of an armored truck years ago.
Both pistols had sights that broke meaning the front of the vial would come off and after a few months they would go dim
Happend to me on a glock 19 and a 22
The sight brand was trijicon. I would bang around inside and getting out going to banks and atm machines. i hope the newer sights are more durable.