Bean seeds 'should' keep for several years. More so if they have been kept in a cool, dark place. If you are not certain about them you could try forcing a few just before the time you would want to plant your crop. Forcing; what I am thinking of goes back to primary school days. Take a jam jar with a strip of blotting paper making a sleeve inside it, push two or three beans down between the paper and glass and pour a small amount of water into the jar. Keep on an inside windowsill for a couple of weeks and "see the beans are sprouting, children"! Assuming that the seeds do sprout then you can sow the remainder with confidence.

Now I wondered where all my primary school teachers ended up!

Now I know...... in the Moray Firth area ;o))

You could also simply put a couple in a 3" pot of compost, and put them on the proverbial 'windowsill' as describe so well by Bulba ;o))

No way, Teegee, just a stupid eclectic memory ;-(((((
A small advantage of my idea is that you can seed the seed start to germionate rather than waiting until something appears on the surface, the root begining to grow before the shoot.