I put my Mac to sleep at night, to make the room dark (also it doesn't wake up once an hour to see if there is anything to back up). In the morning I tap a key and the computer wakes and is ready to go.

You can put a laptop to sleep by closing its lid, and wake it by opening it up. It is possible to put your computer to sleep, disconnect the wires from it, take it somewhere else, connect it up again, and wake it up, and in theory everything should work. Don't do this. There is a risk that your computer will get jiggled and the lid will open while it is being transported, waking the computer, running the battery down, making the computer hot, and risking a hard drive crash. Instead, shut down before moving the computer. I also shut down before plugging in or unplugging a video cable. Power brick, USB and Ethernet are OK to connect and disconnect while the machine is running.

You can set an OS option so the computer will not wake on lid opening, and will require a key press to wake up: in Terminal, type sudo pmset -a lidwake 0.

Do shut down and restart your computer once in a while. It will make it run more quickly. I restart my computer once a week or so, in case temp files have built up or memory has gotten fragmented. My wife finds that heavy use of Adobe Illustrator will eventually cause the computer to get wacky until she restarts.