It depends on several factors: your level of activity, metabolism, diet, menstrual cycle, and personal hygiene.
For example, during your menstrual periods, perspiration can naturally have a stronger odor. Certain foods, like garlic, can also intensify body odor. Stress-related sweating (as opposed to heat-induced) tends to produce a more noticeable odor as well.
In these situations, we recommend washing UNDER after each use.
Otherwise, if you haven’t experienced excessive sweating, it can generally be worn for 2 to 3 days before washing.
In all cases, we recommend daily underarm hygiene to help minimize the appearance of odors.