I imagine a 'composed' riff becomes easier to play with repetition. Instead of searching for notes you know where to find them and how to produce them.

I just listened to Bob Dylan's "Desire" album and recall that he saw a woman walking carrying a fiddle case and stopped and asked her to play on the album. It enhances the whole work substantially. There may be some riffs there you could enjoy to expand your repertoire of possibilities.

There will always be another song to be written. Someone will write it. Why not you? www.garyeandrews.com