[vectorbunny]

You can sharpen a serrated knife with a vise (or jig) and a round or conical file, one tooth at a time. It is a very tedious thing to do.

[gambiting]

I know some chefs and they all say that once a bread knife in their restaurant is done they recycle it and buy a new one - sharpening just doesn't work that well on serrated knives unless you send them to be professionally sharpened in an industrial machine, but then it's literally easier to buy a new knife.

[dmos62]

There's woodworkers who buy unsharpenable saws and throw them away when they're not sharp anymore. There's also those that buy sharpenable and sharpen them themselves or send them to be professionally sharpened. Do what you like.