Fishing line deterioration

[Mike 12345]

If line is properly stored (for example, dark and dry), is there a general rule of thumb as to how long line should last?  How long does it take for it to weaken or deteriorate, if at all?

Thanks

[NBR]

You are going to get a lot of different answers but I have some that is more than 5 years old and it is fine. There is a little bloom on the O.D. but I've not had a problem with knot strength or anything else.

[Marty]

I haven't had problems with line that's years old, I don't know many years, though. But don't store it where it's exposed to the elements.

[The Next KVD]

Think of it this way, you don't know how long the line has been on the shelves or storage areas of sporting good stores.  But I always spray new spools of line w/ Real Magic or KVD line and Lure as soon as I buy it and about once a month during the winter.