It should be replaced as soon as possible to avoid breakage during a swing. Make sure that none of your shafts are loose. If they squeak, there is probably a break in the epoxy securing the head to the shaft. To test your shafts, grab onto the head with one hand and the grip with the other and twist. Any movement or squeak indicates a loose head.
Shafts can become loose through normal play.
The extreme variations in temperature, from day to night, can cause the epoxy to break down. Check to see if your shafts match. There should be a half-inch increment between the lengths of your irons. Woods usually have a one-inch increment, except for some drivers with extra long shafts. These might be three or four inches longer than your 3-wood.