Switch Arcing Mobile Home
Any time you hear that sound, proceed with the utmost caution, there's an excellent chance there's an issue that's a fire hazard.  It might be better to get an electrician to look at this ASAP rather than chipping away at it DIY.  

I'd be more concerned about the arcing generating heat at the arc and damaging your wiring and possibly starting a fire than the arcs damaging your breakers.  

Most of the self-contained switches I've seen are pretty sketchy quality.  If the sound is really coming from the switches, just replace them, but look for any evidence of damage to the wiring from the heat generated by the arcing.  

Arc fault protection certainly wouldn't hurt, you may be able to add it without too much disruption, or it might be a big project.  But you don't want to rely too much on arc fault detection, it may be helpful but it's certainly not perfect - you want to address any issues with the wiring ASAP.