My boat is from 1967. It is more about how long the fuel tank has been allowed to wallow with E10 gasoline in it though. It is the ethanol that phase separates from the fuel over time which picks up moisture and then bacteria (crud) grows in it. This stuff floats on the bottom of your tank so you wont know it is there until you go out on a bouncy day and find that your engine is not feeling so well.
I bought a hand pump that I used to pump about 10 gallons out of the tank.
Beckson Siphon Mate Specialty Transfer Pump
If you don't know when your tank was last tended to it is probably time to find out.