To be certain you'll have touch up paint you will want to buy a gallon or so extra and be sure to have the salesperson write down the exact ingredients of the paint you choose. Luckily, there are machines available which can analyze a chip of paint but, there's that old saying about an ounce of prevention...it could save you from buying gallons later.
Make a difference by making a small change. Pelacing just the top 3 most used incandescent light bulbs in your home with Energy Star labeled compact flourescent lights can cut your annual lighting bill by a third. Although they may cost more to purchase, thay can save enough energy to pay for themselves twice.