Are two year old spices still usable?
You want the "Official" answer? Or the "I Don't Wanna Go To The Grocery" answer?
I'm sure I've used spices that were two years old. Smell of it and see if it still smells like the spice and then taste just a tiny bit. If it passes the smell and taste test, I would use it. The official answer of course is "No" but I don't think the Spice Police visit our forum very often. ;)
I've got some that are plenty old as well. If they taste flat, or more likely, they are as hard as a brick from moisture getting in - then it is time to toss and restock.
The ground stuff.... uhhh.. It guess it depends on what you are making and who you are feeding. Making tacos for the kids? uh huh. Christmas dinner - nope.
whole spices would fare better.
I have found a big difference grinding my own. Especially with things like pastrami.
I was recently on the Durkee site, and they suggested two years for ground spices. Storage conditions are very important. Don't store your spices over or near the stove. Try to keep them in the coolest darkest area of the kitchen.
Some times if your spices are very old, roasting them for a short period of time just prior to using them will boost the flavor a little.