I started doing practice blocks a while ago. It is a great way to test the size of the finished block, check the cutting and sewing order, and test out pressing the seams in a helpful manner. Recently, I joined the monthly block swap. I can try out new patterns, or refine known patterns in the color line of my swap partner and I get a block in my color selection back. So it's a win-win.
If you don't want to make a sampler quilt, you can always donate the blocks to someone who is making charity quilts.