The longest you have owned any gear?

Audio Research SP-7 pre-amp and D100 amp, and Dahlquist DQ20 speakers all bought in 1988 from Wilson Audio in New Orleans, Louisiana. Audio Research gear sold in 2017 (for 47% of original cost). Looking to sell DQ20s.

Revox A77, bought new in '72. ESS TranStatic I's, bought used in '81. Nakamichi BX300, bought new in mid-'80's. Original Quad ESL's, bought used and restored in the early '90's. Townshend Elite Rock turntable, bought new around the same time. An ARC LS-1 and Bedini 25/25, used in mid-'90's. Stax Lambda Pro Earspeakers and McIntosh MR78, used in late '90's. Still own them all.

Polk Model 10A from 1979. They're in my home theater system now. I still use a Burwen Research 1201A for filtering hiss when I dub LP's to disc. A 1977 Army purchase!

Optonica is a name I’ve not heard in quite a while! 

Its nice to go see that some people have gear that provided real long term satisfaction. 

Forgot to mention 18 years old CEC TL5100Z belt drive cd player. Had to change the belt after 3000 hours.