The scientific definition of a machine is any device that transmits or modifies energy. In common usage, the meaning is restricted to devices that perform or assist in performing useful work. It normally requires some energy source ("input") and accomplishes some sort of work.

For your business insurance you need to consider the replacement cost and availability of your machinery. If it breaks down, can you replace it quickly? What will the effect of an extended delay have on your business? Can you rent another unit? How long will it take to arrive?

Other considerations to do with your machinery include the potential liability that a piece of machinery might have while it is in use by another. If you rent out snow removal equipment do you have a hold harmless agreement? Is there a waiver of responsibility signed with each rental contract?

If you own an apartment building then what machinery is heating and cooling your building? Have you considered the impact of an equipment breakdown?

Keeping your machinery values up-to-date is important. At a time when the economy is suffering you can likely buy equipment for a lesser price. Once the economy starts to recover then shipping costs and replacement values will increase. You are the one who has to be aware of the changes and be sure that your interests are protected.