I dont think you would want to sell a Leica if you are a serious photographer. This is a investment for your photography. You can invest to stock market , gold , platinum also but they cant effect to your photographs. You must decide , do you want art , do you want money . All paths are different for you.
If you are from the camp who thinks your zeiss , nikon are better than peoples Leicas , you will not have fun and you have no business with Leica camp.
Lots of people do not understand , read anything from Leica shots here and this forum is not a good place to ask peoples opinion on Leicas.
There is Leica forum at internet but they are so busy to take out of focus 10000 dollar noctilux shots with digital ones.
I think Leica culture lives with rare serious Magnum photographers and dont ask this forum but look at their pictures and decide for yourself.
There are so many americans here , they were using 4 tons cadillacs 50 years ago but today they swear best car is toyota.
You get the point , I think.