I have had solder (stuff I had found in my shop) that was years old and worked fine... I am not wiring up stuff for the Navy
If it flows well, and makes a good solder joint, mechanically and electrically, I think it will be fine for years... I understand in principle it has a life-span but for practical purposes for me, if it works I will continue to use it, as in my case it isnt going to cost anyone his/her life or similar...
Besides, I have never had solder with an expiration date...
I usually go through a 1/2 to a pound a year (I use it for more than amps) so I am good for a while. But I thought it is a good price!
AJC
PS, on a similar note, a friend of mine (older) has a son who workd in aerospace. They use this aluminum peel and stick foil thats wide and thicker than what you see in the hardware store. They have to throw it out after a certain date - and he gets it and gives it to his friends. I have had an old roll (the yare quite large) for years, and I use it for putting into amp cabs, and duct work in my shop, etc. It sticks fine, and I dont know what exactly happens to make it "bad" but it sure is good enough for me! Sticks so good you cant get it off...