He could read the number, not the bottle.

He was pricing the ingredient

Rosemary oil. Castor oil. Coconut oil. He can look up what a litre of any of them costs, and he does, because that is how he buys everything else he owns. The trouble is that nobody sells the ingredient alone. What he is paying for is a decision somebody made about how much of each one goes in, and that decision is invisible from outside the glass.

One thing about the outside does talk, though, and it is not the number. It is what the number does over a year. A bottle that is on sale in January, on sale again in March, and on sale again before the summer is a bottle whose price was never really the price. A number that can fall every month had room to fall. That room came out of something, and it was not the glass.

So read the other four lines

If the tag cannot be read, something else has to be. Every bottle in that aisle makes four commitments, and all four are dull, printed and checkable, which is exactly what makes them worth more than the number. Where it goes. What is in it. How often. And what happens if it does nothing for you.

Golden Oil answers them in that order. Hold any other bottle to the same four.

Where it goes

On the scalp, on damp hair, after the shower. Not down the lengths and not on the ends. That is a fact about where the oil is put, not a promise about what follows, and it is the line that separates a scalp oil from a styling oil. The scalp is where hair is made, so the scalp is where it goes.

What is in it

Eight botanical oils and vitamin E. Rosemary, castor, coconut, batana, jojoba, peppermint, avocado and olive, with tocopherol to keep the blend from oxidising in the bottle. Eight, not nine: the vitamin E is not an oil, and a list that rounds up in its own favour is the first thing this buyer stops trusting.

Jojoba is the one that changes how the rest behave. It sits close to the sebum your skin already makes, so the blend goes in instead of sitting on top. Castor and batana are heavy and stay for hours. Rosemary and peppermint bring blood to the root. That is the mechanism, and it is short enough to check.

How often

Three to five times a week. A couple of drops, two or three minutes of massage. Some men leave it in daily; some put it on half an hour before a wash. A routine that takes ten minutes gets abandoned by March. This one takes two.

The line you cannot write yourself

You have quit one of these before. Almost everyone who has bought a second bottle of anything has. The first one left the pillowcase greasy, or it smelled like a salon until lunchtime, or it simply sat on the shelf being expensive until it ran out and nobody replaced it. Quitting was the right call every time. A product that will not say what it owes you has already told you what it owes you.

Here is what this one owes you, in the only form that counts.

Read the second half of that again, because it is the part the aisle does not offer. Nothing goes back. Not the bottle, not the half of it you used, not a photograph of anything. The bottle stays with you either way, which means the only thing at risk in this decision is a few weeks of a two minute habit.

What you are checking for, and when

Nothing dramatic. More shine. More softness. Better body when you comb it. Those are qualities of the fibre and of the scalp, which is why they turn up in four to six weeks rather than at the far end of a hair cycle. Golden Oil is for hair that is already in good condition and that you intend to keep that way. If you want a bottle to do something else, this is the wrong one, and it is better to know that before you open it.

The window is 90 days. The thing you are looking for shows up inside the first six weeks of it. That leaves you well over a month to decide after you already know the answer.

The man who prices the terms

There is a kind of buyer this is written for, and he is not the one who reaches for the most expensive thing on the shelf on principle. He is the one who stopped reading the front of the box some years ago. He prices the terms rather than the tag: where it goes, what is in it, how often, and what happens if it does nothing. He is unmoved by a discount and equally unmoved by a large number, because he knows the same person set both.

Three of those four lines you can check tonight, on any bottle already in your bathroom. Go and read them. It costs nothing and it will tell you something.

The fourth line is the one you cannot give yourself. No bathroom cabinet contains a promise that the money comes back and the bottle stays. That has to be written down by whoever sold it to you, and almost nobody writes it.