A wooden cutting board with a fish filet and large serrated knife
How Do You Sharpen A Serrated Knife (And How Often Should You Do It)?
By Nick Johnson
Whether creating a stunning sear on a steak or cutting a cantaloupe into chunks, a sharp set of knives is a key player in any chef’s arsenal, and few knives are more versatile than the serrated knife. To keep your serrated knife functioning to the best of its ability, it's vital to know how to sharpen it properly and how often to do it. 
A serrated knife has a set of teeth that catch on food, and since the actual slicing is done by the long flat side of each tooth, this is where the maintenance needs to be focused. Fortunately, serrated knives rely on friction and grip more than sharpness, so while your primary kitchen knife might need sharpening a handful of times each year, your serrated blade can continue cutting cleanly for years.
When the time for maintaining your serrated knife comes around, you can use a handheld or electric knife sharpener that is flexible enough to let every bit of the blade’s jagged edge come into contact with the sharpener. You can also use a honing rod by scraping it along each individual tooth.