Normal blood flow requires 3-6 pads or tampons per day. The average woman only bleeds about 3 ounces during an entire period. Pads, tampons, menstrual cups and Thinx-like underwear can all be used to collect blood during a period. Tampons and pads should be changed every 4 to 8 hours. During a period, it’s especially important to have a daily hygiene routine due to additional bacteria introduced into this area. Cleaning and moisturizing the vulva skin helps prevent infections and dryness.