Our period panties are made to last at least 50 washes, which is far above industry standards. The number of washes is determined by the gusset absorption layer in our Engineered Leak Tech, which has an antibacterial and anti-odour treatment that tends to lose a little bit of effectiveness after 50 washes. It is likely that the function of the panty will last longer though, but 50 washes is what we can guarantee. However, the fabric, form and fit of the panty will last a lot longer. If a panty is worn and washed once per menstruation cycle, it will last around 4 years.​