Get the user of the equipment to give it a visual check prior to use, which is actually the minimum requirement for in service test and inspection of a piece of electrical equipment. It is only a recommendation though. However if it is found to have a problem and then it is still allowed to remain in service and someone gets injured the s*** will hit the fan. This is because it becomes a health and safety issue, and also falls within the Electricity at Work regulations, which are statutory and they will be used to beat you to a pulp in a big way if they are fallen foul of.
So to sum up, if you kit is Ok visually, and is in full working order, then all is probably well, especially class 2 (generally plastic) or 110v equipment.
If anything looks dodgy, then either get it repaired or replace it, but at least take it out of service so no harm can be done.
Cheers.......Howard