If you think there's something wrong with your bike, go to a bike shop (preferably ours of course) as soon as possible. Most things cost less to fix if you catch them early. A part that just need adjusting will wear out and need replacing if you carry on using it. It may also damage other parts of your bike.

Oil your chain. If it looks brown, or makes a noise, it needs oiling.

Pump your tyres up. Unless you're a mountain bike racer, your tyres should be hard, such that you can barely put a dint in them when pressing as hard as you can with your thumb. Properly inflated tyres will make riding easier, help prevent punctures and extend the life of the tyres.

Check your brakes. They should be fully on once you have pulled the brake lever about one third of the distance it has to travel before touching the handlebars. Also, check the brake blocks. They should wear evenly, not with little 'ledges' on them. Spin each wheel, the brake blocks shouldn't rub, or touch the tyre at any point.

A properly maintained bicycle is almost silent. If you can hear it make ANY noise as you're riding then there is something wrong with it. Scraping and scratching noises mean something is rubbing - get it adjusted or it'll end up costing you lots of money. Ticking noises may be damaged bearings, loose spokes, mudguards catching etc. Creaking noises generally mean something needs tightening, or greasing and then tightening. If you can't hear the new noises over the sound of all the other noises you've been ignoring, your bike needs a full service!