If your teeth don't hurt and your gums don't bleed, why do you need a dental cleaning? This is a reasonable question. The answer is simple. Dental disease doesn't hurt until it is very advanced. Gum disease usually doesn't hurt - even when it is advanced. Gum disease is not reversible, however, and what you loose we can not get back. The teeth cleaning, itself, removes the plaque and tartar that is left behind when you brush and floss your teeth each day. If you think you get all of the plaque everyday, it is unlikely. Most people have between 28-32 teeth, each having 5 surfaces; that is 140-160 unique surfaces that you need to clean daily very thoroughly ( a good reason to use an electric toothbrush), 26 of those surfaces are hiding between the teeth, more reason to floss properly. I think you can see that on a daily basis, completely removing plaque from the complex set of teeth that you have is an impossible task. If the plaque is not removed completely then it builds up and can be toxic to your gums causing redness and bleeding gums a condition called periodontal or gums disease. So, the cleaning itself is a preventive measure.
Another part of a regular teeth cleaning is the checkup by the dentist. This catches tooth cavities early, saving you from needing advanced treatments and this saves you money. Once tooth decay has eaten away at your tooth structure, it is not reversible. It can be treated, but treatment is much easier when caught early. If you catch tooth decay when it doesn't hurt, most times you can place a dental filling, but if the decay has gone too far and it has started to hurt the tooth, it is much more likely that you will need a root canal or worse an extraction. The checkup will help catch tooth decay, tooth wear and other problems early before they cause too much damage
If it has been longer than 6 months since your last teeth cleaning schedule and appointment here.