There are used CDT's that can be considered, as the OP has only indicated two Models are of interest and the requirement as being economical it would seem the price point is close to the Models outlined.
With the request to make suggestions of other Models that might be worth considering, it invites a selection to be produced that might extend beyond the price of the outlined models.
This can easily be rebalanced if a used item of a more expensive suggestion is to be purchased.
In relation to wear and tear is it being suggested that a owned and CDT with a few years usage should be expected imminently to become unreliable?
Are all CDT - CDP - DAC used in whatever configuration being confronted with the suggestion that they should be considered for replacement, as concern for their reliability and continuation of correct function are now of importance following a few years of usage, or is this situation only belonging to Models that are considered to be High Turnover Unit Consumer Models ?
My experience do date is that I have purchased a used CDT that is now approx' 5 Years Old from retail purchase and a Bespoke Design Built DAC that is much Older.
The only concern I have had to date for either of these devices is the condition of batteries in the CDT remote control.
I would expect that at approx' $ 600-800, a CDT could be acquired that punches in performance way above the High Turnover Unit Consumer Models outlined, a very highly regarded CDT could be acquired.
It might mean a device is not immediately available off the shelf.
Such an acquisition is to be found, If sought out with the search being carefully undertaken and extends into a wider selection of the used HiFi Market.
