When the light bulb in a light fixture burns out, most people simply replace it with whatever sized light bulb they have laying around the house. This is a dangerous habit that can increase the chance of having a house fire. Every light fixture is constructed to handle a certain maximum wattage. From the insulation on the wire to the insulation in the fixture and the materials that make up the socket, installing a light bulb that exceeds the maximum wattage can cause excessive heating that can ultimately damage the fixture.
Look on the socket of a lamp. You should see a silver sticker that indicates the maximum wattage of light bulb the lamp can support.
Look inside the can of a recessed light fixture to find the label that indicates maximum bulb wattage.
Remove the cover from a ceiling light and the maximum wattage sticker should be located near the sockets and sometimes on the sockets.
Look for the installation instructions that are pre-packaged with new light fixtures. The maximum wattage for the fixture is also usually included in the documentation. In most cases, the wattage is even marked on the exterior of the box so the purchaser will know exactly the type of bulb they need for the fixture.
If the maximum wattage sticker is missing from an older light fixture, stick with 60 watt incandescent bulbs or any sized compact fluorescent (CFL).