A friend of mine has an old SF 6P beater with the "Laser Products" logo on the tailcap, which means it must be >11 years old; he can't remember how long he has had it but he thinks 15 years, which would fit. He is devoted to it and wouldn't change it for anything.
He doesn't use it a lot, but it is always there on a shelf in the kitchen where he can get it when necessary. He says he uses it quite often but probably for no more than 10 -15 minutes total per week, whenever he has to go out and check his car or something like that.
He says he goes through several sets of cells each year, but what is interesting is that he has never had to change the LA - he still has the original P60 incan LA in there. Needless to say, nothing else has worn out on it either, and it has never let him down.