Like any item, if you want it to last, you need to take care of it. This particularly rings true for bikes, as you're also relying on it from a safety perspective. You need to be able to trust the way it will respond, and how it will behave in different weather conditions.
As such, it's important that your bike is well maintained - and this means more than just getting a professional service every so often, or whenever something breaks. You need to take time to get to know your bike, learn how to keep it up to scratch, and identify when it's in need of a professional service.
A great way to do this, is to perform a 15 minute 'ABC-Quick' bike service on a weekly basis.
A = Air
You have 3 minutes to check your tyre pressure. Get a decent floor pump for this - it makes it so much easier that you’ll wonder how you got along without one. They start around $30. Road bikes need to be around 100 psi, hybrids around 70 psi and mountain bikes around 50 psi.
B = Brakes
You have 5 minutes to check your brakes. Make sure that the brake pads aren't too worn down, and double-check that they line up with the braking surface on the rim (the silver part, usually) and aren't rubbing on your tyres. If the cables feel a bit too loose, find the in-line barrel adjuster or similar to tighten them a bit. You can usually do this a few times before you have to either replace your brake pads or adjust the cable tension properly. The most important thing here is that your brake pads shouldn't touch the sides of the tyres.
C = Chain
You have 4 minutes to clean the bike chain. Pop the bike upside down and apply lube to the chain, at the rear cassette (or freewheel, or whatever - at the back hub). The trick here is to put too much lube on, change the gears up and a down through the full range, then use a rag to wipe all the excess lube off by pedaling backwards slowly while holding the rag around the chain. A lot of black muck will come with it. The cleaner it is now, the longer you can go between more thorough chain cleans. Be careful while wiping the chain - don’t let the rag get snagged or your fingers get caught.
Quick = Quick release skewers
You have 3 minutes to check your quick release skewers or your axle nuts and tighten them if necessary. Also, check the main bolts on your head stem, saddle, seatpost, cranks, rear rack, etc. Popping an allen key into each nut/bolt or putting your spanner on it and giving it a quick tighten is a good way to test. You don’t want anything coming loose. Reid has a selection of bike tools if you're in need of a few essentials.
And there you have it, the 15 minute bike service. Your bike is now safer, more reliable, and you know a little more about it. Now it's time to get out on the road!