The premium is the price you pay for an option — ₹500 for a SENSEX call, say. But that single number is really two very different things glued together, and until you can mentally split them, option prices will feel random. Let us split them with real numbers.
Intrinsic value is what the option would be worth if it expired right now. Suppose SENSEX is at 77,650 and you hold the 77,500 call. The right to buy at 77,500 when the market is at 77,650 is worth exactly the difference: 150 points. That part of the premium is solid — it is already true. A 77,800 call, by contrast, has zero intrinsic value: the right to buy above the market price is, by itself, worth nothing today.
Now look at actual market prices. That 77,500 call with 150 points of intrinsic value might trade at ₹230. The extra ₹80 is time value — the market's price for possibility. There are days left before expiry; the index could rally another 300 points. Could is worth money. The 77,800 call trading at ₹60 is pure time value — one hundred percent hope, zero certainty.
Time value does not drain evenly across the week. It seeps out slowly on Monday and Tuesday, faster on Wednesday, and on Thursday it evaporates by the hour. This is why a call bought on expiry morning can lose half its value by lunch even when the index has barely moved: nothing went wrong with the direction — the hope component simply expired on schedule.
An in-the-money option costs more, but most of what you pay is solid intrinsic value that moves nearly point-for-point with the index. An out-of-the-money option is cheap, but everything you paid is melting hope. Neither is universally "better" — but the split explains their behaviour: ITM options reward being right; OTM options punish being slow. In our own execution we lean toward in-the-money strikes for exactly this reason: when a move comes, we want the premium to actually collect it.