In the United States, the U.S. Coast Guard (USCG) requires that all vessels carry a U.S. Coast Guard-approved personal flotation device (PFD) for every person on board. Additionally, children under the age of 13 must wear a PFD while on a moving vessel, unless they are in an enclosed cabin. Specific regulations may vary by state, so it's important to check local laws as well.
at all times when aboard
US - on private waterways/lakes. Some states do not require PFDs at all. On USCG patrolled waters - it depends on the size of the boat, there is a foot length or displacement, over which passengers are not required to wear a PFD.
In Louisiana, every person on a personal watercraft (PWC) is required to wear a properly fitted personal flotation device (PFD), commonly known as a life jacket. The PFD must be Coast Guard-approved and in good condition. Additionally, children under the age of 16 are required to wear a PFD at all times while operating or riding on a PWC.
water skiing or tubing
Those who are required to wear a PFD or Personal Flotation Device by law depends on where you are, and is dependent on what type of water craft you are using. Typically anyone using a PWC or Personal Water Craft (i.e. Jet Ski, Canoe, Kayak etc.) is required to where a PFD. For larger water craft typically anyone under the age of 16 required/recommended, however you are always required to have enough PFDs for anybody on-board the water craft at all times, failure to do so could get you slammed with hefty fines.
when on board a ski boat that is underway
The elements, sun, water, and age can cause a PFD to wear out over time.
Washing your PFD with soap and cold water could cause it to wear out.
Proper size and comfort. No PFD can help if you do not wear it.
Children under 16 are required to have a Coast Guard approved, properly fitted Personal Flotation Device (PFD) at all times while underway on recreational craft.
PFD is required for each person aboardWearable PFD for each person aboard
Exposure to UV rays, among other things, can cause a PFD to wear out over time.