I'd like to add that it depends on your climate and the colors and clothes you wear whether a bag will be year round. I live in Sacramento CA where it gets to be 100 degrees. I wear loads of white and little dresses during the summer so I would put the forest muse away until late fall. But if I wore darker colors such as khakis and blacks, the forest might work even in summer. Look at your clothes and colors and see if you would get year round use.
As another note, I agree $1000 is a lot to pay for a bag that might sit untouched for 4 months. But there is also something wonderful about pulling a bag out that has not been used and re-meeting it and falling in love all over again. And I think it is perfectly OK to have FW, SS and YR (year round) bags. You have that with coats, don't you? I am insanely happy with my Black Crest Easy but I know that come April she will get put away so I can enjoy my summer bags. And my SS bags are "resting" until mid-April. It will be fun to pull them out then.