What is considered a "standard" percentage of devaluation per year foor high end speakers?


As the title of the thread indicates, what is a standard devaluation per year of high end speakers in generally  good condition. 

Often, on Audiogon, sellers ask for 50-to 65% of the retail price for speakers that are between 7-10 years old (or even discontinued) regardless, whether they paid retail or not. 

I realize that condition and the number of owners is a determining factor, and it should be. 

Thank you,  S.J.


sunnyjim
At least 50%  on most speakers if sold on Audiogon
Dealer lucky to get 40% .  Wilson a, B&W and a few other hold value well or if Hot with several great reviews . Rule of thumb sell if possible a few weeks after a nice review ,and link to the ad.
I have sold nodded speakers night and day better then stock 
But most Audiophiles know little about Xover builds ,just parts name  you get little extra back for your efforts.
To roberjerman:   DCM Time Windows are/ were a terrific speaker for their time in 80's.  I sold them in mid-to high end store in Pennsylvania. The shape of their cabinet is still being duplicated today by many manufacturers.    

You cannot listen to %

Buying second hand is the way to go. Let rich people pay the most %.

To willydewoofer  Actually my question is based on a speaker that is 4 years old and still  retails for $3500. The issue in this context is not "sound quality", but determining reasonable devaluation from retail.  

I am not going to pay retail. I don't think sellers seem that desperate at this time, if I am correctly reading AG's speaker listings. Though, there seems to be several  big ticket speakers in the 15,000-30,000  on the selling block


To shadone: If you claim Elisabeth "nailed it"  with her devaluation formula, I will clean up a pair of Rectilinear 7's in the basement and put them on sale.  I think they were current in 1973 and designed  by Richard. Shahinian who passed away in November 2017