Cast/tubeless and it's held air this long, probably fine forever. I've had a couple flaired spots on one bike for the last 70k miles or so.
When was the last time you checked air BEFORE getting the ding?
2010 690 EnduroR
2013 500 Exc
20+ years, 100k+ miles, 15 state's, 5 Countries, 3 years on asphault looking for the checkered flag, 7 dirt trying to stay on my minute.