Teak oil tends to darken and dull with time. All of the teak I have seen on the factory C Dory have been a light oil finish. On my trim, I clean it once a year and then put a lite coat of oil, let it soak in about 20 minutes and then use a soft cloth to take off any excess.
There are many ways of treating interior teak. I find the oil to be the easiest. Always be careful of using any harsh chemicals on teak. If you scrub with the grain and a brush, you will remove the soft wood, and leave a raised hard grain. Any cleaning with brush should be across the grain. I just use Dawn soap and scrub it well. Wrinse and let dry well, before oiling.
On our larger cruising boats, some of which were all teak below, we varnished with a satin varnish about once every 3 to 4 years. We mostly sanded before re-farnishing--not much yearly maintenance.