Lightbulbs come in different wattages, neck diameters, fittings (bayonet or screw) and styles, such as regular bulbs or candle bulbs. But when one goes, you don't want to be spedning time working out which one you need.

The widest range (and better brands) of low-energy lightbulbs are not available as readily yet as ordinary bulbs, so it can be an inconvenience to find the right one in a hurry. A list, and an idea of where to find the ones you want, can be a help. So why not make a moment to go around your house and make a list of all the different sizes and types you will need?

Although it would be expensive (and unsustainable) to replace all your lightbulbs at once, a list will also help you to stock up on a few bulbs and save money by ordering over the internet. When you are ready, you can Google to find a good internet price.