Changing oil before the book interval on the 450, worth it?

Saw this on Team-BHP, an owner doing a lot of hill climbs in low gears found the oil tired out well before RE's quoted 10,000 km service interval, so they started changing it early instead of waiting. I ride a fair bit in the ghats too, mostly second and third gear on climbs. Is it just me or does that interval feel built for plains riding, not actual Himalayan terrain. Anyone here getting oil checked or sampled themselves, or just trusting the manual blindly.