No, not really. Granite counters don’t need to be sealed, but doing so helps the surface resist etching and staining caused by dirt and spills. As a construction material, granite is naturally resistant to moisture. However, it is also porous. Sealants prevent liquids from seeping into the granite and eroding it over time.
If you decide to go ahead and seal your counter, the best granite sealers to use are the ones that consist of tiny particles dissolved in liquid. From my experience, I found that Tuff Duck Granite, Grout, and Marble Sealer delivered the most bang for my buck. I resealed our granite counter about a year and a half ago and it still looks new today.