The asphalt should go through two winter / summer seasons before it is sealed. Sealing fills in the minor voids between the stones of the asphalt. You should have it done by someone that uses a good product that has some substance to it. I have seen driveways sealed that is more of a color coat, than a sealer. I personally like the oil based sealer that is mixed with an asphalt and sand mixture. This will fill in the voids and help to keep the driveway looking good for years to come. Avoid at all costs the latex sealers that come in the can at the home center. As for your contractor saying that if he doesn't do it, it will void the warranty, he is blowing smoke. Check with your States Attorney General and see what he / she has to say about this. Read your warranty contract and see what it says. It would have to have been written into the contract before you had the job done to be enforceable. Just like your car warranty. They can say that it is void if you don't change the oil, but they can't force you to do it at the dealership.
