Hi All - I am hoping for a little help with finalizing which Shapton glass stones I am going to pick up. I have been freehand sharpening for about a year now. I have an Atoma 140, DMT C, DMT EF, Spyderco UF and strops. I am pretty happy with my results but now want to try something new mainly for curiosities sake. For now I have settled on getting some Shapton glass stones. I am also interested in trying the Venev resin bonded diamond stones, for my "super steel" folders, but that is probably a purchase a few months down the line. My question is regarding the longevity of the Shaptons. Based on what I am OK with spending I can either go 500 double thick + 2k, or 500, 2k and 4k. Is the double thick 500 necessary? I am a casual sharpener, say 5 knives a month. Ill be using these stones mostly for friends' kitchen knives so likely a lot german steel. Additionally, I am a hobby knife maker currently using 1084 for utility kitchen and outdoor knives. Would I be OK using the Atoma and DMT C to set bevels on my new knives and repair really damaged edges and then move into the Shaptons? I can't seem to find good information on the actual longevity, in terms of knife sharpenings on these stones. Everyone talks in relative terms. My current thoughts are if I am ok to use the diamonds for my really course work then that should help extend the life of the 500. Then I could go with the 500, 2k, 4k set up. How long should these stones last with my sharpening volumes? Lets assume I am a light to medium pressure sharpener. Lastly, from what I have gathered I am OK to flatten the Shaptons, even the 4k, with my Atoma 140. Please let me know if that is incorrect. I am open to any other suggestions as well. Thank you all in advance!