How often to clean/lubricate viewfinder orings

I have the old style Nauticam 45 viewfinder. I am yet to find any info on how often to clean/lubricate the twin viewfinder piston seal orings. I often dive in my local river mouth and the water is very silty, as bad if not worse than most Indonesian muck sites. If possible I would only like to remove it for travel or an annual clean/lubricate. Can members with experience on this viewfinder chime in with their experiences?

Thanks Chris

I travel with mine a lot and only take it off the housing when it is packed in the backpack ready to fly. Before each trip (so 5-6 times per year or every two months or so) I lubricate the 0-rings with Tribolube. Even here in Los Angeles they can get quite full of muck. Also, make sure to carry a spare set, they are quite thin and you want to make sure your trip can continue if one somehow breaks.

BIll