regular checks of equipment is a must

Things eventually give way, so regular checks are necessary to avoid major problems. Take this for example...

These hoses connect the pump in the pond to the external filter, and back from the filter to the pond. This one has split due to age, and the only thing keeping the water in is a layer of algae. 

If the hose from the pump in the pond to the external filter had split, it would have been catastrophic as the pump sits at the bottom of the pond. It would have drained out most of the water. I have placed the pump slightly elevated on a brick to lessen the problem in the event it does happen.