While everything has a natural expiry date, a good quality piece of woodwork should not be letting you down anytime soon. With that in mind, I highly recommend investing in some Clear Penetrating Epoxy Sealer (CPES) from this website. For me, this is a must-use on all wood products I make. This will preserve the wood, stop it from rotting internally, and it will do a good job of making sure it lasts for as long as it should.
Good quality wood products should be something you do not have to worry about falling apart anytime soon. If you have made a wood product or bought an untreated one, then I would use some CPES on it as soon as possible. Trust me; it will keep that wood looking grand for longer.