A long time ago, I was a student. I was in my 12th (means final year of schooling, next up engineering). I had an exam the next day. Like always, I thought "let me study later, the day is still young and I have all night long to prepare."
So I started watching some highlights of a soccer game I had missed. Then came Dragonball Z. Then came something else, something else and so did the evening. It was sunset. Suddenly lights went out. But why? My dad had got an inverter installed an year back, I had UPS backup? It was then I realized there was a major power cut from morning and I had used up most of the battery.
WTF! My exams.. So while I was still like "Meh.." my parents freaked out, sometimes power never used to come back till next morning those days (actually sometimes even now). So we decided, we'll use the power judiciously.
So when I was studying, other than the one light in my room everything else was switched off. Then when my mom went to cook, only the kitchen light was on - and I waited. So using 1 light the whole night long, managed to pull it off without tripping the inverter.
You are probably thinking why I wrote this now?
Well... Unity just released a new version and you can have 1 dynamic light in the free version ^_^
Just saying... 1 light can make a big difference.
Also, a contest [See what I did there? O_o]