Every company will tell you that the panties will last up to 12 hours.
You can wear some panties for 4 hours, some for 6 and others for 12 hours. But it depends on the strength of menstruation and your comfort.
You need to test this first and find out what suits you.
For starters, we recommend e.g. 3 pieces, which we have with a 20% discount, and then you can see for yourself.