All good points. Will think about this proposed purchase further, particulary the motivation.
I wouldn't necessary call lens "consumer goods" as they are tools to do a job. I don't have a 85mm prime, so that's where the need came up. I could buy a cheaper/generic 85mm for 1/3 of the price, but I beleive CZ lens hold their value very well over the years and I should be able to enjoy the glass and sell for a profit if that need ever arises.
All of my other lenses have risen in value since the time I bought them (mostly used).
Unless you are using it in a professional capacity, it is a consumer good. If you are earning/saving money on this, then it is a tool, and any investment in it must be judged as such (will this earn/save me more than I will pay for it, and will it do so in a way I could not before).
I'm not going to jump on the 'deserve mind-set' issue, it's been talked about, but it seriously, no one deserves a consumer high as payoff for hard work.
I'm a fellow photo-nerd, and I understand the want for new gear. No question, the Zeiss optics are nice, but here's my question - will the improved sharpness bring any extra value to your system? I recently jumped into the Medium Format (film) pool, and chose to go with a Bronica setup instead of a Hassy. There is no question, the Hassy has better (somewhat) glass, but the chance of the Hassy making a a picture
I take any better than the Bronica is infinitessimal. There's a lot more holding my photography back than a line or two per mm of lens sharpness.
Will the CZ prime improve your photos $500 worth over a similar lens? Will the enjoyment of using that lens be worth $500 to you?
You mention selling it later down the road for profit as a justification. This rings hollow to me. Generally speaking, lenses are depreciating assests, even Lieca lenses sell for less used than new. Unless the CZ is a screaming deal, any increase will likely be related to inflation, not increasing value. Which means you'd be better off investing the money and getting dividends.
So, assuming the CZ is $1k, and a near equivilant lens is $500 (you said 1/3rd, so I'm bumping it up to 1/2 to play it safe):
-Will the CZ make improve your images in a meaningful way beyond the alternative?
-Will the enjoyment of using the CZ be worth the opportunity cost of going with the alternative?
The opportunity cost is $500 investments + $20/year dividends. Put another way that's $500 stached plus:
-5 rolls of film if you swing that way
-or 75 4x6 prints from a pro lab
-or 5 8x10 prints from a pro lab every year
One last thing that can't be measured: Your wife's feelings need to be considered in this.