Dental sealants can last up to 10 years under the right conditions. However, if you grind and clench your teeth, this can shorten their lifespan. It also depends on how much hard food you eat. The more hard food that you eat, the less likely your sealants are to last 10 years.
A single tooth getting a dental sealant applied to it is $50. Typically molars are the only teeth that get sealants applied to them so you can expect to pay around a maximum of $600 for a full sealing procedure.