Hair mask or conditioner? Read the job description.

Haircare shelves make masks and conditioners look like two separate worlds. In practice, the useful question is what a particular formula is designed to do and how its maker tells you to use it. A word on the front of a jar is not enough information to build a routine.

Wella describes conditioners as routine products for manageability, and masks as more intensive treatments that may have richer textures and different application times. This is a manufacturer’s explanation, not independent evidence that its products outperform alternatives. Read Wella’s comparison.

Put the two labels side by side. Record the intended hair type, whether each product is rinse-out or leave-in, its application time, frequency instructions and bottle or jar size. Then add the price you will actually pay.

If the instructions describe essentially the same role in your routine, pause before buying both. If one takes more time than you realistically have, consider whether you will use it consistently enough to make it worthwhile.

Do not borrow another product’s directions from a video. A mask that says three minutes does not automatically become better when left on overnight. Equally, a leave-in product and a rinse-out product should not be treated as interchangeable. Follow the instructions for the item you own.

When a brand recommends using two products together, recognise that as the brand’s proposed routine. It is not evidence that everybody needs both. An independent decision starts with the gap in your own routine.

Suppose a hypothetical $18 mask contains 200 mL and you use 10 mL each time. That is $0.90 per application. This arithmetic cannot tell you whether the product works for you; it can tell you what the extra step costs.

Use the cost-per-use calculator with your own numbers, and keep the example separate from any product recommendation. We have not tested or ranked products in this explainer.