I've bought a battery from batteries plus and a light + casing. The battery is 12V 5Ah and the bulb I'm running is 12V 20watts.

My question is how I can wire this. I was thinking just running the positive terminal on the battery into a switch and then onto the light and the negative directly to the light, however some people were talking about how I'd need a fuse for my light so i don't catch the battery on fire.

Is it really that important to have a fuse or can I just do some simple wiring?