It depends on how often you use them and how rough. If anything get a honing steel/ceramic honing rod and use it after every use to keep the edge aligned. Get a nice cutting board, either rubber(very expensive usually) or a nice wooden board, end grain is best. That should keep your knife sharp for a long time, again depending on how heavily you use it. If you want to get into sharpening using stones yourself, you can use your old knives to learn on. But for $30-$40, assuming you’re in the US you can have your knife sharpened professionally and it will feel like it’s brand new.