Topping higher end gear holds value. This is true but only until they replace that with something else. The D90 has value now only because there is no higher end topping available and everyone has a feeling that that’s the best possible DAC out there. The moment it’s replaced, suddenly it loses its value tremendously. Remember what happened to the A90 amp. When the A90D came around, the Orginal King lost its crown and it now can be had under 250 which is half of its retail. A90D Still retains value as there is no replacement available, with a higher number like 95 or 100!! People mistake A70 pro to be a step below even though every metric says it’s superior to the a90D.Higher end Topping DACs seem to hold their values well enough, blame this forum for it.
Don’t buy Topping used, instead just wait around on Amazon. I have noticed that the D90s drop the price occasionally on Amazon by 200 bucks. I got mine for 599 on that last sale. Recently on Black Friday it was 599 again, which is mostly the asking price of a used one these days.