Even a high-end knife won't hold an edge forever. There are multiple 'systems' out there. I've gone from Chef's Choice pull-through spinning disc systems (just like the ones in commercial kitchens but without the discs being on an easy-replace cassette) to water stones to a Worksharp Ken Onion belt system.
The CC had the advantage of being quiet/clean enough that I could do it in the kitchen but the actual edge was short of splitting-hairs sharp. Stones got plenty sharp enough but took forever (make sure you have a long podcast). I finally landed on the Worksharp. About as sharp as stones but as fast as the CC.
Both stones and belt give me a convex edge; the CC has a 'trizor' edge which IMO isn't appropriate for Japanese (harder) steels.
The CC is the easiest to learn, then the WS, then stones. Both WS and stones are messy. Stones when in use need a large space in the kitchen. The belt system thows off enough dust that I use it in my garage shop.
Hope that helps someone...