A general rule of thumb is after 2 week the coffee is probably not good. Now that doesn't mean you still can't use them. It just means that they will not taste as good. Coffee beans begin to oxidize as soon you open the bag. which means that the coffee starts to lose flavor. While it will not make you sick to drink it; you probably won't enjoy it all that much.
The best way to store coffee is to freeze it. If you have a large bag of coffee make sure you separate into to smaller bags. That way your not freezing and refreezing your beans. Frozen beans last 1-2 months. The best way to freeze coffee beans is to store them in airtight container. When you are ready to grind them take them out of the freezer and grind them immediately. They do not need to be defrosted. Do not bother trying to freeze ground coffee and don't put them in the refrigerator. It's not cold enough to keep them fresh, and your coffee can pick up the smells and flavors from the refrigerator.
You can keep coffee beans for an extended period if they are raw beans. "Green coffee beans" will last up to one year. They are hard to find, but well worth it if you are a coffee lover. Usually the best place to find "green beans" is online; most stores do not sell them. There is nothing better than fresh roasted coffee, and it can be a lot of fun experimenting with roasting techniques.
Bottom line is try to buy the amount of beans that you can use within two weeks. Don't try to stock up on coffee unless it raw.
Uses for old coffee or used coffee grounds:
Make an exfoliating body scrub with the coffee grounds.
Mix in 1/2 cup of coffee grounds with some body oil or baby oil and scrub away. (it can also help with cellulite)
Compost coffee grounds or add it to your potted indoor plants.
Use coffee grounds to chase off ants and snails.
Make soap and add in for extra exfoliation.
Deodorize your freezer with coffee grounds. Put them in an open bowl and place them in the freezer it will absorb the odors.
