Very few fleas make it through the entire lifecycle of the flea, as most die in earlier stages before they reach adulthood.
That is because for fleas to reach adulthood they must successfully obtain a blood meal from a suitable host and if they are unable to do so they will die before reaching full maturity.
But an adult flea is capable of living for up to about two years if all conditions are optimal.
You may reference the illustrations of the flea life cycle in our image gallery for further information on this subject.