I have been using a Spyderco Sharpmaker with great satisfaction for several years - not much there to wear out -possibly new rods? I learned on typical flat whetstones, which are cheap, durable, and sharpen well enough. There are also "pull through" gadgets which do a decent job, unless you are really into sharpening, doing much more than cooking and opening packages.

Sharpening knives seems to be one of those infinite rabbit holes into which you can plunge