This is the biggest problem, most people envision free energy forever and forget to allocate the savings as future investment. I am a Power System engineer and over the past 20 years have regularly been asked to give advise to friends and family with regards to installing solar systems. The biggest reoccuring cost is battery replacement systems rapidly deteriorate after a certain amount of time, and also are very sensitive to temperature. This is all fine if you make sure you put assisde a few hundred dollars each year in preparation for the replacement but a lot of people fail to do this.
Really the best solution isn't a homeowner solution but a community implemented solution. That way they can pool resources, have a committee to manage expenditure and levy fees and organise regular inspections and maintenance.
The biggest downside to being an engineer is realising that everything is in a constant state of decay and it requires real effort on behalf of society to keep everything running smoothly. I wish i could go back to being innocent and thinking everything was great :). On a positive note I am very certain we have the technology to improve society for the future, and if you want to go down the rabbit hole try looking into virtual inertia.