How old is too old for a Dac?

@andyz I know what you mean so happy about my AN dac-3 Signature now wondering how much better the Balanced might be? Happy for now, very happy, but good to know there's an upgrade path!

OP
In other words, how old is too old for a dac?

When you and your family, friends, have embraced a technology that the old DAC no longer supports.  

@ ct0517

Do I need to clarify that my question was regarding SQ?

Spoogemonkey

IMO - You need to form your own opinion before buying/committing, especially if there is a large $ outlay.

With digital, I would bring my existing DAC (whether it is a CD player or a dedicated DAC), whatever your current reference is, into the Audio Salon and have the dealer substitute it in, with the others they are offering and compare. This allows for multiple comparisons at different price points.

This will allow you to form an opinion.

fwiw
I have been told by different dealers in the past that the digital business is on a 2 year cycle as far as product turnover, new product is concerned.