Carpet cleaning is essential every once in a while. It will ensure that a carpet is cleaned deep down, so that all the fibres are freshened up. This will help to make it smell better, get rid of allergens and improve the appearance.
You can clean a carpet yourself with off the shelf products. You need a professional cleaning company to provide a proper carpet clean though. They will use a carpet cleaning machine that shampoos the carpet and then washes it, removing the shampoo and all the dirt along with it. This is injected deep down into the carpet fibres to really freshen it up.
Carpet cleaning is useful if you have stains and marks that you want to remove. You may simply decide on a carpet clean anyway though, as this will help improve the condition of your carpet and will make it fluffier, fresher and better smelling.