There two types of samples in my sewing room: New techniques trial-outs & materials/tools reference.
Every time I sew a new fabric or technique, I make a little mock up with a sample of the fabric to test various stitches, interfaces and techniques. I love keeping those for later reference. I write the machine feet, the optimum stitch length and even tips on the fabric. When I don’t have a project/fabric in mind I would use muslin as the seam finishes mock up above.
The other type are samples I keep of materials I order on the internet. Particularly great to use later for my trials. Stabilisers are particularly helpful because I will trial a variation of those on the final project sample material and then decide what result suits my purpose before I order the right amount. This can help realise repeated choices. If the case, ordering bolts would result in a cheaper price.
Another fun & useful sample I own are a visual reference of the various types of stitches available on my machine. Instead of having to refers to my manual, I can see a visual representation of the result stitch. That’s very helpful for me as my machine has 294 different stitches…
I’m interested to know, do you keep samples and how useful they are for your sewing?