The MAS FAQ has good info on this, assuming that's the epoxy you're using.

https://masepoxies.com/faq/  

You're probably still fine, I've used epoxy over a year old, but not much longer than that. Try mixing a small amount and see how it comes out.

I would, however, make sure your pumps haven't gunked up over time. I made that mistake and ended up having my ratio being way off, which made for some nasty cleanup on a thwart.

Well, I guess to be safe I will buy new material.  I would hate to think to save some money; I used bad epoxy only to find out later on that I am having problems. 

I have used epoxy that is more than a year old. Just warm it up in a sink full of hot water until it flows well and it should be OK.   

Yeah, just use your old epoxy and make up a test batch.  Coat a scrap piece of wood to make sure it cures hard overnight at room temperature.

Thanks, guys, will try a test batch.  I guess if it cures well then there should be no degradation at a later date?