It's not water on the surface that is the problem. It's the water that gets under the asphalt that weakens the sub base of the driveway or road that causes the problems. The water strips away at the integrity of the sub base making it weaker and therefore more cracks appear.
Because the asphalt surface over time become more and more brittle it continues to crack and can form potholes very quickly after a big downpour.
Get onto sealing them now - it will save you plenty of money in the years ahead. I can't tell you the millions of dollars i have seen go up in smoke because asphalt life has been shortened because of a lack of maintenance. By shortened the length of life of the $100000K by 3 years is an extra cost of $20000 to its owner. That's big money and if you take good care of it you can lengthen it out and make savings of $30000 easily. Easily!!!
Where did I get these figures? Let's assume an asphalt carpark should last 15 years (that's a good life), that's a cost of $6500 per year. If you don't look after your asphalt it means you have to come up with the cash much sooner than anticipated and if you lenghten its life you are effectively saving yourself time and therefore money because the next resurfacing job.
Below is a quick video of how easy it is to reseal a crack - anyone can do it. There are products on the market, but the most popular and easily to use for the home owner or even the smaller contractor is Bitumend Crackfix.