I get a real kick out of hunting down the best value for every little currency in 'Old School RuneScape', so here’s how I think about kudos. First off, kudos are almost always worth spending at in-game reward shops tied to minigames and seasonal events rather than on one-off consumables. Those shops usually stock things you can't get easily
Elsewhere — cosmetic items, unique skilling outfits, and quality-of-life gear. In my experience the top-tier purchases are untradeable uniques and outfits that give small but consistent bonuses: they stack over months and suddenly you
realize the kudos bought you a smoother grind.
Another angle I use is opportunity cost. If a shop offers an XP lamp or a bank-saving item, I’ll lean toward that when I’m mid-skill grind. Cosmetics are tempting, but if you’re chasing efficiency, buy the items that save run-time or resources. Also keep an eye on seasonal stores: holiday NPCs sometimes rotate rare vanity items into those shops, and because they come only now and then, they’ve got the highest subjective value. Lastly, consult community price threads and your own goals — PvM, skilling, or collector — then spend kudos where they align with your long-term plans. For me, that’s usually a mix of one useful skilling piece and one vanity item I’ll actually wear, and it makes the whole grind feel worthwhile.