How often should you seal your countertops? 
Generally, we recommend resealing your countertops approximately once per year. With the amount of money one spends on material and fabrication the minimal dollar amount it costs to reseal is a very wise investment. If you maintain/clean your countertops regularly with natural stone cleaners (our or T&M Neutral Cleaner) your sealer should be effective for 3-5 years.
How do you know when to reseal?
The best/easiest way to determine if your sealer is performing would be to apply a drop of water at least ½ inch in diameter to the top of the stone and let it sit on the stone for at least 15 minutes. Cover the area with a glass to inhibit evaporation. Wipe off the water drop, if the stone did not darken then your stone is sealed against water-based stains. Testing for oil repellency is not as simple because if your stone is not sealed, you will have an oil stain.
What should I use to remove a stain on my stone countertop?
First, you wou
ld need to identify what type of stain you are dealing with. If it is an oil base stain, Oil + Stain Remover by Stonetech would be your best option. If it is an organic stain, a dry poultice mixed with water should do the trick. After stain removal, reseal your countertop with your preferred sealer. We would recommend Bulletproof by Stonetech as it is a water based sealer, and perfoms better than any other water based sealer on the market.