My family buys a 1/4 side of beef every year, and we also stock up on groceries when they are on sale and put them in the freezer.  I also regularly make freezer meals.  Simply put, our freezer contents are very valuable to us. 

I read somewhere that if you take ice cubes and put them in a Ziplock bag, you can use them to monitor your freezer conditions.  For instance, if you go out of town for a week and come home to find all of the ice cubes melted and refrozen in a solid block in the freezer bag, you know your power was out for a significant amount of time, and the freezer contents may no longer be good. 

This is a simple, low cost method to monitor my freezer contents when we have been away from home for an extended period.  Works for me.