One of the more common fluorescent tube, lamp or bulb types is the T8 lamp. Fluorescent tubes are measured in eighth-inch increments, meaning a T8 lamp or bulb is one-inch in diameter. They are quite energy-efficient, can be purchased practically anywhere, and are quite easy to change. Additionally, they are manufactured with a variety of wattages, and range in length up to 8 feet. With a life-span of as long as 25,000 hours, it's possible that this is the first time you have ever needed change out a failing T8 lamp.
Your T8 bulb may be equipped with two contact pins on each end. Fluorescent tubes of this style are referred to as either "Bi-Pin" or "2-Pin" types. The pins slip into the grooves installed in the sockets located at each end of your lighting fixture. You insert the pins into both ends of the fixture and rotate the bulb until they lock into place. As T8 lamps are manufactured in a wide variety of lengths, it may be helpful to measure the length of the bulb in advance, or take the old one with you when you purchase the replacement.
Fluorescent bulbs are extremely brittle and will likely shatter if accidentally dropped. Be careful, as fluorescent tubes are coated inside with mercury. If you should drop a bulb, work slowly and deliberately when sweeping up the fragments. As a precaution, you may wish to slip on a pair of work gloves to protect your hands. If you will be replacing the bulbs in an overhead fixture, work from a sturdy stepladder. It might also be helpful to have another individual on hand to receive the failed bulb and pass you the replacement. They can also help by holding the ladder steady.
Single-Pin T8 Bulbs
Unlike their "Bi-Pin" counterparts, some T8 bulbs are equipped with only a single pin. To remove one, simply push the bulb in one direction until the opposite end is free, and then lower it out of the fixture. Then install the replacement in the opposite fashion. Single-pin T8 bulbs are usually manufactured in 4- and 8-foot lengths. Because they are somewhat easier to install and remove, they are often the preferred bulb for hanging fluorescent fixtures, such as shop lights. However, they are just as brittle as their "Bi-Pin" counterparts, so exercise caution when working with them.