The directions are once daily, preferably in the morning, which already tells you this is a habit product.
A one-time fix would be taken when needed and judged immediately. A daily option is judged over a stretch of consistent use, which fits the guarantee wording: use it consistently for at least 30 days, then contact support within 60 days if you are not satisfied.
Write down your start date, keep the time of day the same, and decide in advance what would count as a difference. Without that, a month passes and you cannot say whether anything changed.