Females spend the intervening time at sea. Nesting seems to occur in 2 and 3 year cycles. Hatching is one of the most dangerous times in a sea turtle's life. Young turtles must pass through a gauntlet of hungry predators as they crawl across the sand to the ocean. Once young male sea turtles reach the safety of the ocean, they may never set flipper on shore again for the rest of their lives.
Hatchlings find the sea by heading towards the light.
The ocean is the brightest source of light at night. The sex of baby turtles is temperature-dependent. Back to the list I've heard that sea turtles live a long time. So far nobody knows the answer to that question. All sea turtle species are considered endangered or threatened in at least part of their range.