The life of the driveway can be extended by re-sealing it occasionally. It depends on the severity of the weather and its effect on the driveway. When the surface starts looking white, better start thinking about resealing.

When you have a lot of cracks, you should fill those, before re-sealing. If you have no cracks, you can do the sealing with no other effort. It comes in 5 gal buckets, you pour out a puddle of it and with a long handled squeegee (at least 24-36" wide), you just spread it over the surface. You don't want a thick layer of it. You're essentially "painting" your driveway with the sealer.

It'll prolong the life of your driveway for you though.

Good Luck.