How about the rear ones?
The internal attachment to the bike includes a simple, steel 'hook' feature. With age and vibration, the hook gradually opens up and allows the entire turn signal to vibrate and then wobble around. Like a snowball, the failure grows more and more rapidly until the stalk snaps off. Periodically inspect by grasping and shaking. If not perfectly tight, remove the blinker and whack the 'hook' with a hammer to flatten it down square to or parallel to the base. Reinstall and reinspect next year. Last forever if you keep them snug and don't crash.
Patrick Hayes
Fremont CA