The main function of patches is to provide fabric protection on an area that gets a lot of wear and tear so the life of garment is extended. One of those areas is at the elbow which is why elbow patches are pretty common on jackets and sweaters. These days, elbow patches can also be a fun style detail. It adds an extra pop of color, can make something boring into something more unique, and you can do a different shape, like a heart. You can use all kinds of fabric for the patch, you just want to make sure it has similar care instructions as the garment. While adding leather patches to your sweater sounds cool, you could be turning that easy washable sweater into dry clean only strictly because of the patches. The downloadable pattern allows you to make your own patches, but you may have to resize them to fit your purpose.