The sealer penetrates the patio concrete stain and goes into its pores, slowing future water penetration and minimizing unwanted staining that comes from things like rusting flower pot holders, leaves, and other stuff that gets left on the patio. A good grade concrete sealer can last for years before needing to be reapplied and usually just requires power washing the floor before putting it down again.
One thing we always do when we seal patio concrete stain projects is to include some type of skid resistant agent in the sealer coat. A sealed concrete floor on its own can be a little slippery. By incorporating a skid guard, slipperiness is reduced. One type of skid guard we use is called “Shark Grip” which consists of very finely ground polyethylene beads. These plastic beads are mixed into the sealer, which is then sprayed onto the floor. The beads are spread in a thin layer and act like transparent sandpaper particles, decreasing how slippery the sealer is, even when wet