Hi, hoping someone can help please?

I am conducting some research into chiller efficiences and would really like some advice and answers to the following questions:...

In terms of running a shop keeper's chiller/fridge as efficient as possible..what are your recommendations to achieving this?

If a retailer was to turn their chiller off in the evening, does this save them money overall or will they use more power by switching it back on in the morning? Does it make a difference?

Is it more cost effective and energy efficient to have the chiller maintaining a constant temperature?

Maintenance: What conditions make a chiller break down? What are the best practices to maintaining a fridge/chiller to preserve it's lifecycle?

Many Thanks in anticipation.