Unlike asphalt, you can start sealing concrete driveways immediately after installation (with asphalt you should wait till 3-6 months after installation). Sealing concrete driveways every 3-5 years thereafter is good policy, as severe weather breaks down your coat of sealant over time.
Asphalt driveways are commonly re-sealed every year (where winters are harsh) or every other year, depending on your climate.
For more on caring for asphalt, please consult my article on sealing asphalt driveways.
Much of the work involved in sealing concrete driveways is preparation. That includes preparing your body for the job. Sealants are rather unpleasant products, so avoid skin contact with them (wear gloves, long sleeves and long pants). Before sealing concrete driveways, make sure the surface is clean. That will be the key to the whole operation, so that the sealant can adhere properly.
You'll probably find it easiest to work on one small square section at a time (a section, say, 10-20 feet square) when sealing concrete driveways, rather than doing long narrow strips. Apply the sealant in thin, overlapping coats with a long-handled application brush or squeegee. One coat usually provides sufficient protection. Drying time is about 2 hours.