Here's what the Atomic Aquatics manual have to say:
"The major service interval for the Atomic Aquatics regulators is semi-annual (2 year) or 300 dive. We recommend that you take your regulator to an authorized Atomic Aquatics dealer annually for a safety inspection."
Don't know if things have changed with Oceanic but it used to be (for personally owned equipment used for recreational diving activity):
"Equipment used 100 dives or less per year should be serviced at least once per year. Equipment used more than 100 dives per year should be serviced after 100 dives prior to further use. Equipment stored for more than 6 months should be inspected, and serviced as required, prior to use."