Granite despite the fact of it being naturally hard is really porous. And the best way to keep the liquids from penetrating its porous characteristic is by applying a granite sealer. You can apply this for at least once a year and if your budget allows, then make it once every six months. When you seal it, it enhances its capacity to last longer and steer away from all scratches, marks and other etchings. It may be moisture resistant but its porosity is what makes it vulnerable to other liquids like oil, spills, greases and juices.
The frequency of the sealing would really depend on the porosity of the granite you have in your countertop. So it cannot be helped that there are some countertops that would require sealing for more than once a year. Before you even start to seal it, it is important to apply some tests first. You can do this on your own just by dropping some water. If it gets soaked easily, then it is the right time to reseal it. If it does not, then give the granite a few more days or maybe even a month and then do the test again.
To apply the granite sealer can be done in a very easy manner that you do not need to hire a contractor to even do it for you. You should only get a granite sealer that is non toxic, a granite cleaner and some soft and very clean cloths. The sealers also come in two types which are topical and penetrating. The penetrating type of course penetrates well on the granite stone when you apply it. You must clean the countertop and let the cleaner just sit on it for about 30 seconds.
Then rub it dry with your clean cloth before you apply the first coat of the granite sealer. You must wait for about 3 to 4 minutes till it is absorbed well by the stone already. When it becomes dry, you must then apply another coat and rub the clean rag and repeat the process for at least one more time. If your granite is used in your kitchen countertop, then choose the sealers that are oil repellant so that it can really help in avoiding the oils and greases from seeping to it.
On the other hand the topical kind of granite sealer builds up some film or coating to cover the surface of the countertop. It also comes in two categories like permanent and strippable. The strippable is more prone to wearing and tearing easily and you can remove it easily anytime you want to. While the other one which is the permanent type is solvent based and water based which is not recommended for granite. It is tougher to remove them but it is really a better choice for countertops if you want something that would last long. It would just need some regular resealing every year for it to be always kept maintained and looking good.