What is uscg meaning of serviceable condition for pfds?

Serviceable condition for PFDs according to the USCG:

A PFD is considered serviceable if it meets all of the following requirements:

1. It is in good condition and free from damage, deterioration, or defects that would affect its performance.

2. It has been properly maintained, inspected, and tested in accordance with the manufacturer's instructions.

3. It has not been modified or altered in any way that would affect its performance.

4. It is of the appropriate type and size for the intended use.