Early dental decay is often not painful, you may not be aware of your dental decay.
If dental decay is left undiagnosed and untreated it spreads deeper into the tooth. This can lead to a dental infection, with symptoms including tooth ache, sensitivity to hot and cold, pain on eating, and sometimes inability to sleep due to pain.
It is much simpler (and less expensive) to treat early decay than it is to treat a dental infection. Even better, regular visits to a hygienist can help you to avoid dental decay.
So if it is quite some time since you’ve been to the dentist, a check-up might be a good idea. (See ‘How often should I visit the dentist’ below)