How long is line good for? I was cleaning the garage and found a few spools of Berkley Big Game. I know it is at least 4 years old. Is it still ok to use?

I think it most likely would be fine, but me; I ask myself do I really want to trust a possibility of a once in a life fish on some old mono I found in the garage lol... Me it would go to the recycling bin. That's my thoughts about it.

That is a good point. Not really worth the risk.

It's not really in my opinion anyway.

Maybe use it as backing line.

Considering the Academy H2O Express mono line is low priced. There's no reason to temp it. I guess you could test it by a dead weight lift.

Otherwise, I also vote to use it as backing. That's what I do with my old spool of mono. It's also way older then 4 years. I'm guessing 2010 vintage. It's still going strong but new line is worth the peace of mind.

Sunlight and high heat is the reason most mono lines go bad. I have some Excalibur co-polymer that is at least 25years old that I still use. It has been stored in my shop all this time. I have never had a problem with it. I would put it in a line test against any new line out there. The reason for it's age is I was on their staff my moons ago and had gotten a ton of it in various line strengths. I used it all this time while guiding and traveling the tour route. It has never let me down. Excalibur was the old Silver Thread. I still have some and use it now when I go chasing Bull Reds.
I have found that if it you pull it through you fingers and get a white residue the line is most likely bad.
All that being said this is just my experience.

Micheal- I used to sell Excalibur Silver Thread line- it was the best line I had ever used. If you ever want to sell a few spools let me know. Thanks.