1. I really should... 2. I promise that I'll... 3. I swear I'll / I won't... (a very strong promise) 4. No matter what happens, I'm going to... 5. Come hell or high water, I'll... #4 and #5 express your determination to do something, even if obstacles appear.
This is a pet peeve of mine. I hate it when people leave lights on when they are not using them.
30% of a home s energy usage comes from the lighting. Turning the lights off when you leave the room can dramatically reduce the amount of energy used for lighting.