how long do night sights last?

[wcoats]

I have a Sig P226 with night sights. It was made in 1995, and the night sights still have a good glow to them, which seems kind of impressive to me. Just out of curiosity how long will night sights last? And how much brighter are new ones than some that are 15 years old?

 

[BADUNAME37]

Radioactive Half-life - 12.3 years

http://www.physics.isu.edu/radinf/tritium.htm

 

[wcoats]

hhh, so i guess that means my night sights are less than half as bright as there were at first

 

[mbopp]

Actually the eye has a logarithmic response to light. So while it may be half as bright your eyes won't notice much of a difference.

 

[lions]

^^ Did not know that. Anyone know how many years until they actually need replaced?

 

[JohnKSa]

I know it's a simplistic answer, but they need to be replaced when the user decides that they are too dim. Different users are going to have different thresholds so it's going to vary a lot.

 

[raz-0]

Little vials end on, you will likely notice them being pretty dim at about 10 years. Mainly because they are marginal to start unless your eyes are dark adapted.

Big vials you should get longer out of.

I have a set of each kind that are about 10 years old in my possession, and not more than 12 years old as far as I cna figure out. The small ones are better than nothing in a dark room, but they are pretty useless in dim lighting. The big ones are still pretty useful in dim light.

 

[BullfrogKen]

About 10 years is a good rule of thumb.


Is there any way of knowing if your sights were factory installed or installed somewhere after it was purchased? Or if they were replaced once somewhere in it's life?