I live in an RV, and my goal is to move “off the grid” without a steep decline in my standard of living. This requires reduced power consumption. Lighting sounds like a good place to start:
I measured the DC current consumed by two incandescent cabin bulbs (2.7 Amps) and then that consumed by two LED replacement bulbs (0.2 Amps). There is an order of magnitude in difference (13.5 times). This means that a 100 Amp-hour battery running the two incandescent bulbs can last for 37 hours, while the same battery powering the two LED bulbs can last for over 500 hours. (In practice, you wouldn’t want to run a 100 Amp-hour battery to empty like this–it would damage the battery–but these measurements demonstrate the point).
LED lights are expensive; I don’t recommend making the switch to save money on electricity. Instead, make the switch to help make your batteries last longer between charges.