Awesome suggestion from Sayonil above, I know what I’m doing with my afternoon
Those techniques can also breathe life into a riff that’s relatively recent
It’s also worth noting that our tastes evolve and our writing styles develop which can feel like our older material sometimes doesn’t fit with who we are now. A recorded/written piece of music is essentially a snapshot of who we are or were at a given point along our musical journey. To counteract, and satiate our artistic side, its often the case where we just need to go back to the drawing board and create something new
Definitely keep everything you write though because what sounds stale to you personally may sound totally fresh to a bandmate who’ll inevitably end up twisting and sculpting it into something that you never thought possible. Also, using the snapshot analogy, older pieces of music are like personal photographs, sometimes it’s worthwhile just comparing who you were musically at one point to where you are now