Okay, so I have been vacillating on whether or not to get a D850 and join the herd, or to wait for Nikon to come out with a mirrorless equivalent to the D850.
(I must've ordered, and canceled, at least three D850 purchases in the last month +
)
I finally decided to go for it. I hit the "buy" button ... and waited ... and waited ... and waited ... but the 'backorder' status remained.
[As a side note, forgetting I was a NPS (Nikon Professional Services) member, I contacted my local NPS representative on Friday, and today (the very next Monday), my D850 has been shipped and is in route, via overnight delivery
...
NPS IS GREAT 
]
However, the purpose of this post is trying to share my thoughts in assessing
the cost-versus-depreciation risk analysis in an environment where purchasing expensive gear for a DSLR (that may quickly become extinct) has been troubling to me. My tax guy and I considered the alternatives.
Right now, in my growing business, most of my purchases are write-offs anyway, so I am in a good position
However, even if I could not write anything off, the D850 + the 3 additional 'E' lenses I intend to purchase really don't add-up to much, all things considered.
Since, my desire is to purchase the D850 + the 8-15mm E + 28mm f/1.4E and the 105mm f/1.4E ... added-up,
this is a roughly ~$8,500 expenditure for a top DSLR + 3 top E lenses. (I pay cash, I don't finance, so there is no hidden interest rate to worry about.)
My tax guy asked me to give a reasonable time period for the life expectancy of this purchase. I told him
10 years,
but he divided that in half, 'just to be safe.'
- $8,500 total ÷ 5 yrs. = $1,700/yr.
- $1,700/yr. ÷ 12 mo. = $142/mo.
- $142/mo ÷ 1 wk. = $33.15/wk.
- $33.15/wk. ÷ 7 days = $4.75/day.
In reducing a seemingly-large purchase, factored by considering the years of service, and then
dividing down to the week/day, it's a ridiculously-low price to pay to invest with the best camera + optics in their respective classes.
Together we reasoned that waiting for 2-3 years (or beyond), for a complete mirrorless system "to develop", would actually
cost more (in downtime) than just buying perfectly-great equipment
now, enabling myself to use it now, and then sorting things out for later.
There really is no way to lose WORST CASE SCENARIO: In 5 years, my DSLR + lenses are worth nothing, so what does that mean? Er, I've been able to enjoy fabulous gear
every day, for 5 years,
for the cost of a hamburger/day 
;
MID-CASE SCENARIO: In 5 years, mirrorless are prevalent, but my gear can still be sold at $0.50/ on the dollar (or even adapted to mirrorless), so I've been enjoying superb gear
for less than $2.50/day ... and can still enjoy it
;
BEST-CASE SCENARIO: In 5 years, both mirrorless and DSLR are still out there, they're just two different niches, and (as above) I've been enjoying great gear all along ... while others are "waiting" ...
In all cases, equipping myself 'now' (rather than 'waiting') makes the most sense.
So I will have my D850 tomorrow ... and I am no longer worried about 'whether I should wait or buy now' ...
now is the time 
