Doug, I believe it depends on the actual component of the kit in terms of long term storage. Supposedly stock bleach solution will last forever but the first developer less so. I use the Kodak 6 step and chuck the working solution after one use. I generally use up the kit in about a month or so and I have seen no ill effects from storing the stock solutions in partially full bottles for this amount of time and they could probably last longer but I'm sure PE can give a more adequate answer. FWIW the 6 step process is foolproof as long as you strictly adhere to the instructions and I have never screwed up a roll of film. For the better longevity of your images and the apparently better image quality I would go with the Kodak 6 step process but thats me. The most time consuming part is mixing the dilutions but after that it flies.