shelf life How long can thermal paste last new sealed in box?

[chromalife]

I have a friend that seems to have stumbled upon an entire box of Thermaltake TG-7. I know it has to be at least 2-3 years old. My question is, is it still good? I had a tube of the same stuff and it went bed after about a year after opening it. The packaging says that it's good for 24 months after MOB, but I'm not sure if that's just the company covering their rear ends. 

[CommanderAlex]

I know Noctua's NT-H1 has a shelf life of 3 years if unopened and actually used at tube of it that came with my Noctua cooler that sat for over 3 years old and seems to be good. As long as the thermal paste doesn't look like it separated like some tubes of toothpaste. I've also used a tube of Arctic Silver 5 that was over 5 years old and worked pretty good to be honest. 

[SupaKomputa]

I have a big tube of thermal paste i bought 10 years ago, still good.

If it's still gooey / wet i think it's good.