The shortest life span I know of occurs in some squillids and is a couple of years. Most gonodactylids live from 3-6 years. Some large lysiosquillids live much longer, perhaps 20 years.
We have very little data on O. sycllarus, but my guess from early growth and molt frequency in aquaria is 5 years - perhaps a bit longer. The longest I have very kept on was a little over 3 years, but that was starting out with a sexually mature adult.
Roy