Typically, about 1 3 days of counting time is required. In spite of many uncertainties, this method gives fairly good idea about the age of the sample up to about 60000 years.

Will all of carbon-14 eventually disappear?

The half-life of carbon-14 is the amount of time it takes for one-half of the original amount to disappear by radioactive decay. After 50,000 years, a fossil wont have any radiocarbon left in it. Carbon-14 will have all disappeared by radioactive decay.

How long does it take carbon-14 to turn into nitrogen?

5730 years Whereas its cousins take mere minutes or hours to decay, only half of the carbon-14 component of a given substance is gone after 5730 years, having become nitrogen-14.