The bulb can be lit for about 20 000 hours before it needs replacing. If you have dimmer switches in your home, you can use bulbs such as this one.
From Amazon
Osram 18 Watt 4 Pin Compact Fluorescent Daylight White 865 Light Dulux Lamp
LED Bulbs
Osram 18W Dulux CFL DE 4 PIN Daylight - OS564944
Big on Electricals
Osram 18W Dulux CFL DE 4 PIN Daylight - OS564944