The correct amount of chain lube must be applied regularly to prolong the life of your drivetrain. A chain with the correct amount of oil should look somewhere in between dry and manky black. Try not to go wild with the oil when applying it, this results in a wet oily chain which attracts dirt. The dirt will then grind down your drivetrain components resulting in gear crunching and eventually a broken chain. Only use bike specific chain oil and apply one layer to your chain whenever it feels dry. Do not apply WD-40 or similar to your chain, this will only attract even more dirt. Applying excessive oil not only results in a worn drivetrain but it also results in a very oily and frustrated Grease Monkey.
Another common mistake seems to be applying oil based sprays to disc brakes to stop them from squealing. DO NOT apply anything oil based to your brakes. It may sound silly but many people seem to think its a good idea to apply lubricant to a stopping device. This results in having very little stopping power, noisy brakes and much hilarity amongst the Grease Monkeys. If you need to clean disc brakes use brake specific cleaners. Make a ‘chain-ge’ and use a small amount of oil to protect your bike and your wallet.
Keep the pedals turning!