How many whetstones should I buy when starting out?

While it is tempting to buy every grit available when starting out, we recommend getting one or two high quality whetstones first. Preferably you should get something #800-#1000 as your first stone. This will be the stone you learn most of the hand sharpening on. In addition you can get a medium polishing stone between #3000-#5000 grit. With these two stones, you'll be able to focus on forming good habits and consistency. 

Once you developed the muscle memory, good habits and adequate consistency, you can start exploring other whetstones options. Lower grit whetstones are useful for blade maintenance and chipping repairs, while ultra high grit finishing stones will help you create extremely refined edge and finishes, for cutting performance and aesthetics. Whetstones are half science and half art, so there are some personal elements to it. Some prefer a certain feedback, while some like the aesthetic result of certain stones. Some go extra miles to find a certain natural stone from a certain volcanic quarry in Japan in order to achieve a certain aesthetic appearance for their kasumi polish. Once you are consistent with hand sharpening, you'll open the door to exploring all these fun options.