My 1980 boat has the same amount of teak as any 1987 GB 42. When I acquired this boat in 1993 the interior needed freshening, mostly to get rid of cigarette smell. Since that fresh coat of semi gloss varnish it has had another, and in some places I am considering doing it again. The floor gets high gloss, some of the trim as well, but most of the teak gets semi.
My exterior teak OTOH all gets gloss. Some boards are ready for their second coat, but most get it semi-annually or annually. I keep Retreat in a shelter 6 months and in the weather 6 months.