How often do you change components?

A speaker review started off by stating the reviewer's reference system, and the recent changes he made to it. So how can he determine the sound of the new component in the chain? I know the audio upgrade bug bites hard, but if one continues to swap components, how do you keep your reference point? How ofter do you make changes to your system? How long do you live with th change before making another? Thanks
My reference is live unamplified music so no matter how often I make changes my reference stays the same.
I try to keep a component at least four to six months. Many components can take up to 600 hours to break in and settle. (ie: Audio Research SD 135 Stereo Amplifier)

After break-in I usually will take another three or four weeks to put it through its paces with various types of music and power cord trials.

A few times I have been undecided and had components waiting in the que to be added to the system. If it is a deal and the price is right I may take a flier on a piece that I anticipate working well for me. I can worry about selling the loser later.

I once had four SACD players and three pair of speakers at the same time. Rare for me! Everything I was looking for came on the used market at the same time!
With every tire rotation.
When I averaged it out over the long term it worked out to about one major component per year.
Nice one Audiofeil.
While in SQ flux, about once every 2 years.
Do your audio friends listen to and scrutinized the differences in you car audio system after the rotations?
Once a week!!
look under Tbromgard's system for my 2 cents worth on this subject. SORRY for the dumb mistake...!