I've been sewing for more than 30 years, wearable art and quilting for the last 20 or so. I have a huge stash and am gradually using a lot of it up. Amazingly, my taste in fabrics hasn't changed that much. Possibly because I rarely buy what is considered the latest and greatest so I just keep chipping away at what I have. When I want to start a new project, I first look at what I have on hand and then buy whatever I don't have. I'm also making a strip quilt right now that has used up a lot of fabrics that I had that were left over from other projects.
While I do need to use up some of what I have, it's not something that I actively worry about. It'll happen. Or it won't and some other quilter will benefit after I'm gone.