What is a Tafo amp?
As to your question about tube life in the "analog" output section of a CDP. My experience with a Jolida 100A which used 2 X 12AX7s was that after 4 years of constant use measured and performed as essentially new.
I had rolled true NOS Mullard military spec tubes into it with a very dramatic improvement in tone over the stock Chinese tubes. I regret that I don't know what their function was but I am certain they were in the signal path. The tubes did show some signs of aging with darkened flashing. (This is said to be a function of gas absorbtion only... but coincidently is often seen with older tubes).
