After roasting they will keep for about 6–9 months if they are sealed.
It is best to store them in an airtight container. I own a vacuum sealed coffee bean container on my counter. It’s overkill for me because I go through it in less than a month.

I do the same as @Forever_Free, I buy from the roaster (Graffeo Roasting Company in San Francisco) and they stay in great shape for a week, second week they lose a bit of their freshness, but are still good for a pot of coffee (I go through a pound every 10 days).

If you do not use the beans quickly, you can keep them in an air tight constainer in the freezer and they will last a very long time, like a year. When we had a vacation house, we woud keep beans in the freezer for months.