Setting up Inverter and external charger w/ new batteries

Having lithium myself I enjoy reading and following folks reseaching, piecing/ building it. It seems at times in these threads that because it's lithium batteries an "inevitable failure coming" which could happen in any of our systems. So having somesort of backup plan is prudent but we aren't living in some 3rd world country here where civilization or parts can't be had in a reasonable amount of time.