When it comes time to apply a fresh coat of stain on your decking, you will need to get rid of the old stain first. The two most common ways of getting rid of stain is to either sand or strip the deck.
Stripping uses chemicals to remove any existing finish from decking. This can even remove things such as mold, wood grain tannins, mildew, and algae from the wood. These chemicals are able to better open the pores of the wood and penetrate it better. Stripping is much faster than sanding, however, the chemicals can be quite harsh depending on the product you opt for. It will also be important to wear a mask so that you don’t inhale the fumes.
Sanding of course involves sanding away at the surface to strip it back to the bare wood. For the majority of sanding jobs you will need a power tool. This can be very time consuming depending on the amount of decking you have, and may not be possible on some decking depending on where the screws are. Sanding will also make your decking thinner.
To choose the best between the two methods, you will need to weigh up how much time, effort, and money you have to get the job done.