If you prefer short hair, nearly trimming your sideburns is all you need. As a general rule, it is advised not to cut them higher than a quarter-inch from where your ear sits on your head. There is no need to shave your sideburns, and doing so could create a bigger problem for you, causing unwanted and prickly stumble.
Should I shave my sideburns with long hair?
It's up to you, but it's probably a good idea to trim them on occasion. As you grow your hair out, your sideburns may become a little unruly and hard to style. Trimming them back regularly will keep them from sticking out to the side while your hair is getting longer.