Subject: Does the age of a drinking glass effect its brittleness?

My mom has some old glass drinking glasses that she hasn't used in years.  She 
says she doesn't want to start using them now because if you don't use the 
glasses on a regular basis, they become more brittle as time goes on.  She says 
they tend to break a lot easier when you wash them.  Does this make any sense?  
Isn't glass just glass?

Re: Does the age of a drinking glass effect its brittleness?