Service on Sea and Sea dSLR housings

Sea & Sea recommend sending their housings to their authorised workshop for service and replacement of all internal o-rings once a year. At least in my part of the world, this is an expensive business. Is it really necessary? How often do you send your housing for service?

Depends on how frequent you dive... I have seen people doing in less than a year.

Considering minimum diving I would send it in at least once every 2 years.