Should I turn the water off to my home during a winter absence?
Wow, this got long but after 2 times replacing pipes and a toilet in a detached garage this is what I learned to do many years ago. After that we have not had problems, but we're in a warmer climate now....

If you turn the water off please turn the power off to the water heater or if gas turn it to pilot. If there will be no heat at all and your area gets below 27 to 28F it would be a good idea to drain the water heater. Turn the main water supply off, or if on a well drain the pressure tank first, then open the sinks, flush the toilets and last open the outside hose bibs or faucets. This will pull as much of the water out of the pipes possible and even if the water in the pipes freeze there won't be solid water to expand and break the pipes. 

This is what I found on exterior water lines in out buildings that were not heated with -23F and a wind chill of -80+ or cold enough to toss a hot cup of coffee 5-6 feet and it hit the wall like a shlushie (don't do this with white walls because we thought it was fun did it maybe a dozen times on the detached garage the next spring I had to repaint that side of the garage from the big brown spots but it was fun). 

So if unheated drain water turn power off flush toilets and you should be ok. It took me 2 years to get it right but no problems after that.