Many of the problems could be related to storage, poor fuel, etc.. Insure proper storage habits, maintenance, and inspection, pay attention to gauges, know what’s normal for the machine, listen to it, feel for vibrations or changes, check and change fluids regular and inspect what comes out, lube all friction points, etc... the new rubber is designed to deteriorate so it won’t sit in a landfill indefinitely, the new fuel has ethanol which corodes and attracts moisture. Electronics simply fail from time to time... a weak battery could have caused undue stress on the alternator, voltage fluxuations, and possibly affected the ignition components... the fuel pump, if electric could have been a cause or effect of the other electrical issues, or if mechanical could have failed due to the impact of bad fuel or deteriorating rubber parts... bearing failure could be from inadequate lubrication or damage from moisture or maybe lost pre load or the like... storage is hard on machines. I deal with similar issues with my equipment. I use much of it seasonally, so it sits and I end up having seemingly unnecessary repairs... maybe carry a basic tool kit and some spare parts? Like in high school, lol... one thing for sure, if I run off and forget my cell phone, fate seems to punish me every time.