Most people assume mining hardware is a fixed sunk cost when it often can be converted back into operating capitol - although at a value lower than acquisition price. As far as I can tell - the only hardware that absolutely becomes trash after 1 year is an ASIC miner. USB risers, motherboards, CPUs, RAM and of course video cards all have some value after 6 months or 12 months of mining.
Every 2 months (or more frequently if the market is crashing) I evaluate if I am losing more in devaluation of my hardware than I am earning mining profits. In Vosk's case he's earning one tasty Chipotle burrito a day - and I'm sure tails takes most of that. But 50 cards may be losing 2 to 3 burritos a day in value.
I think the 1070 and higher cards will hold their value decently well, but the 1060s and 1050s are going to crash hard (4k and 144Hz monitors demand more than a 1060).
But it always must be considered how hard is it to liquidate a video card in a deflating market. Right now it's. In January I was selling 2 year old RX 470s with 1 year of warranty for $450 cash (the nice MSI Gamer X ones, not crappy blower ones) in Los Angeles. I posted them as mining cards and told the buyer the optimal settings I had found.
If you try to sell a card now you'll probably say "was never used for mining" and when they ask you what games you played at Ultra High you say CS:GO
Losing total burritos by the day is a depressing statistic DrG!
Sad to think about that hardware price drop, reference top of ebay search today