That's an excellent question, and the honest answer is: it depends entirely on your desired look. Unlike other woods, teak is incredibly durable and doesn't *require* oiling for protection. Its high natural oil content resists rot, insects, and weathering. Oiling is primarily a cosmetic choice.
If you prefer the rich, golden-brown honey color of new teak, you will need to re-oil it regularly. Typically, for benches exposed to full sun and rain, this means applying a high-quality teak oil 2-3 times per year (annually at a minimum). The key sign it's time is when the wood turns a light gray or silvery color and feels dry to the touch.
Here's a simple process:
1. Clean Thoroughly: Use a specialist teak cleaner to remove dirt, mildew, and the old gray surface.
2. Dry Completely: Let the bench dry for 24-48 hours.
3. Apply Oil: In dry, shaded conditions, apply a thin, even coat of teak oil with a brush or cloth. Avoid over-application, which can create a sticky film.
4. Let it Cure: Allow 24 hours before using.
However, many garden enthusiasts embrace the natural aging process. Left untreated, teak will gracefully weather to a distinctive silvery-gray patina, which is equally beautiful and requires zero maintenance. This patina is a stable, protective layer.
Final Verdict: Re-oil 1-3 times a year to maintain the golden color. For a low-maintenance, elegant look, simply let your teak bench age naturally to silver. Either way, your bench will last for decades.