Check what you are buying: Some stores have been selling low-cost low wattage LEDs which whilst decorative don't provide enough light to replace bulbs used to illuminate rooms or read by. Use the table above as a guide.
Dimming LEDs: Whilst LEDs can be dimmed most LEDs sold are not dimmable. If you require dimmable LEDs you'll need to purchase LEDs designed to be dimmed AND change the dimmer control for one designed to work with LEDs - most dimmers used with standard bulbs won't work with LEDs. We've also found that the LED bulbs and dimmers have to be matched to ensure successful dimming.
Low Voltage Bulbs: Low voltage halogen bulbs (MR16 fittings) often found in downlighters, can only be switched to LED if a wound transformer is in use. If the fitting is powered by an electronic power supply (typically a small box) then the chances are LED bulbs won't work properly. The best bet is to move away from low voltage downlighters to 230-volt bulbs using GU50 fittings, which don't need a power supply.
Bulbs Sizes: Most standard bulbs can be replaced by LED. Some LEDs including standard, downlighter and candle bulbs can be larger (usually longer) so if available space for example in a flush light fitting is critical then check the LED size before buying or specify a smaller bulb type.