How long do marine invertebrates live?

As with many other aspects of their existence, the lifespan of marine invertebrates varies widely, depending on the species.  In general, many live for a number of months or even years.  For instance, sponges can live for a few months to more than 20 years.  Octopus and squid live for 2-3 years on average.  Then there are species like corals, which can live for hundreds of years.