Lighting takes up only 10 - 15% of energy used in homes today. With the price of LED lighting coming down this percentage could be cut by half or more. But why continue to pay for electricity for lighting at all when you can put out an initial payment on equipment and then be free of this charge on your monthly electric bill? Maintenance to a solar lighting system would primarily include occasional battery replacement. Other maintenance issues might be storm/hail damage (covered by home owners insurance---check with your insurance company) to solar panels or failure of electronic components such as a charge controller. On the bright side if you install a system and it lasts five years then hopefully solar panel production has increased and lowered the cost of your replacements. Not only would future solar panels be cheaper, but advances in the technology should also increase their efficiency giving you more bang for your buck.
I'm starting small. This is a simple solar night light.