Some things can fail, and are a pain in the arse but you can still ride to the next town or to where you can get help.
A fine example of this is a clutch slave cylinder. You can ride any distance without having to use the clutch.
Start the bike in neutral pointing downhill, let it roll and snick it into gear, then use clutchless gearchanges.
If you're on flat ground, again start the bike in neutral paddle it along and snick it into gear and away you go.
Essentials..
Take a used (but you know that works 100%) hall sensor.
Alternator belt (the longer 611 belt, and check if you have the shorter 592/582 belt fitted. They make the alternator sit low against the top of the engine case, and on many bikes you can't fit the adv tank link pipe through unless you remove the alternator belt and raise the alternator. By using a 611 belt you don't have this potential problem).
Final drive bearing and seal.
And last but not least ...... The small "O" rings used on the fuel Q/D's.