This article from TextileArtist.org is a nice read if you have ever wondered about the value of sampling stitches or techniques before you start a project.
Sampling can be addictive. It's all about the "What ifs" that keep popping up as you try one thing, then make some small alteration to the process or color or thread weight and try it again. Even better is when you let one idea link to another and another . . .
The reward of all this curiosity spread across small pieces of fabric is that the samples are making your own encyclopedia of stitch and technique ideas as they begin to fill a box or a bin. Notebooks with cloth pages (the holes are made with buttonholes) hold mine. I've even used Pellon as a page, which keeps the pages from folding over in the thick binders.
If you searched the dark corners of your own studio space, how many samples could you collect? Enough to fill your own ring-binder notebook? Maybe two notebooks? My favorite ones are where I start out a little loose and not so nice, but as the stitching continues, I can see the improvement I make. Seeing where you came from is often a great teacher. And mistakes might be the best teacher of all, because we learn more from mistakes than doing things perfectly the first time.
Don't forget other fabric techniques-- Felting experiments can lead to a new direction in wet or dry felting. Fabric manipulation gives texture, whether perfectly or imperfectly worked. What about painted Lutradur or Bond-A-Web, heat-manipulated surfaces . . .
Take a moment to read the article about sampling as a creative process. It might be the impetus you need to start your next project!