Upload & Sell: Off
A rough cost-benefit analysis of purchasing a 600 MK II:
In the simplest form, a cost-benefit analysis would involve comparing two alternatives, weighing the advantages/disadvantages, and selecting the best choice. In this illustration, I assume Alternative I as buying a 600 MKII and selling it after 5 years. Alternative II is keeping the cash in a savings account, assuming you are using surplus cash rather than borrowing to finance the purchase. I also assume (1) the useful life of the lens is 20 years, meaning I would depreciate it over 20 years on a straight-line basis, and (2) interest rate on savings would stay the same for the next 5 years. Overall, I use a very conservative approach in this illustration, meaning the actual benefit may be more than what I show.
I also assume you take 5,000 nice pictures a year.
If so, the cost of owning the lens for a year (out of the 5 years you keep it) is $723.57. The cost of one of the nice pictures you would take is 14 cents. Isn't that cheap?