The longest you have owned any gear?

Spatial Coherence Preamplifier is definitely the oldest thing I own - a 1977 purchase.  Next up is a bunch of Amber 70 power amplifiers.   About the same time frame I purchased a pair of Shahinian Diapason speakers with four subwoofers. Pretty much everything else I own is much newer although my Conrad Johnson electronics have been around since 1997 or so.   

Still my TT. Purchased in 1983. Responded in 2017. 

My current gear:
Cary 303 CD player I have been owning since 2001.
Altec 604E speakers since 2005.
EMT 948 turntable since 2011.

ROWLAND 8T 12 years it is still a classic amp.

I've own my Acoustat Spectra 33 electrostatic speakers since 1988, 33 years. I use them for maybe a week or two every few years.