Please find common practices on how to take care for your Casio watch:

• Never try to open the case or remove its back cover.
• Exposure to very strong electrostatic charge cab cause the watch to display the wrong time and can even damage watch components.
• Electrostatic charge can also cause lines, which resemble circuitry, to appear momentarily on the display. This does not have any effect on the function of the watch. You should have the rubber seal that keeps out water and dust replaced every 2 to 3 years. 
• Should moisture appear inside the watch, have it checked immediately by your dealer or a Casio distributor.
• Avoid exposing the watch to temperature extremes.
• Though the watch is designed to withstand normal use, you should avoid rough use or dropping the watch. 
• Do not fasten the band too tightly. You should be able to insert your finger between the band and your wrist. 
• To clean the watch and band, use a dry soft cloth or a soft cloth moistened in a solution of water and a mild neutral detergent. Never use volatile agents (such as benzine, thinner, spray cleaners, etc).
• Avoid allowing the watch to come into direct contact with hair liquids, colognes, sun block creams and other toiletries, which can cause deterioration of the plastic parts of the watch. Whenever the watch comes into contact with these or other toiletries, wipe it off immediately with a dry, soft cloth.
• Store your watch in a dry place when you are not using it. 
• Avoid exposing the watch to gasoline, cleaning solvents, aerosol sprays, adhesive agents, paint, etc. Chemical reactions with such agents will destroy seals, case and finish. 
• Painted finishes can be discolored and worn by very strong pressure, long term rubbing, scraping, friction, etc. 
• Some models feature silk screen printing on their bands. Be careful when cleaning such bands so that you do not rub on the printed designs too hard.
  
  For watches equipped with resin bands:
• You may notice a whitish powdery substance on the band. This substance will not harm your skin or clothing, and can be removed by simply wiping it with a cloth.
• Leaving the resin band wet with sweat or water, or storing it in a area subjected to high humidity can cause the band deteriorate, cut, or crack. To ensure long life for the resin band, wipe off dirt or water with soft cloth as soon as possible. 
  
  For watches equipped with fluorescent bands and cases:
• Long-term exposure to direct sunlight can cause fluorescent coloring to fade. 
• Long-term contact with moisture can cause fluorescent coloring to fade. Be sure to wipe all moisture from the surface of the watch as soon as possible. 
• Long-term contact with any other surface while wet can cause discoloration of fluorescent colors. Be sure t keep moisture from fluorescent surfaces and avoid contact with other surfaces.
• Strongly rubbing a printed fluorescent surface with another surface can cause the color of the printing to transfer to the other surface.
  

You can find Casio Manual through the following site by just entering the 4-digit module number, which is available at the case back of your Casio watch.

To find Casio manual: http://world.casio.com/wat/download/en/manual/

The Full Auto Light feature automatically illuminates the face of the watch whenever it is angled towards your face, but only in the dark or when surrounding light is dim. The face is not illuminated automatically while the Full Auto Light feature is turned off, or if your watch is not equipped with the Full Auto Light feature.

Normally, the solar cell and rechargeable battery should be able to last as long as the watch.

If your watch has a one-step sleep state (see Question 3, above), alarms and the Hourly Time signal sound while the watch is in the sleep state. If your watch has a two-step sleep state, alarms and the Hourly Time signal sound while the watch is in step 1 of the sleep state, but not in step 2 of the sleep state.

This indicator appears to let you know that the battery is recovering after a large load is placed on it over a short period. All tones and the light are disabled during recovery. The indicator should disappear and normal operation should resume after battery voltage recovers.
If the RECOVER/RECOV indicator appears frequently, it means that remaining battery power is low. Leave the watch in bright light so it can charge.

The watch is designed to automatically enter a sleep state and shut down the display to conserve power whenever the watch is not exposed to light for a specific amount of time. The sleep state is indicated when either "SLEEP" or "S" is on the display (either flashing or steady). Click here for information about how to exit the sleep state.
Some watch models have a two-step sleep state. In step 1, just the display is turned off, as described above. If the watch remains without light for a number of days, step 2 is triggered, which shuts down all watch operation, except for timekeeping.  See the User's Guide that comes with you watch for information about its sleep state.
Important!
The watch will enter the sleep state only if its power saving feature is turned on.

Place the watch in a location where it is exposed to light. If display characters do not reappear or the CHARGE indicator starts flashing on the display after about five seconds, it means that battery power has gone low. If this happens, leave the watch exposed to light until the CHARGE indicator disappears from the display. Note that all of the watch's buttons are disabled while the CHARGE indicator is flashing on the display.

Please click here for detailed explanation.

It depends on the model of your watch. Look at the back cover of your watch and find the three- or four-digit "module number". Next, click here for information about approximate required charging times for each module.

Yes. The watch should be able to keep on running as long as you keep it exposed to indoor and outdoor light as much as possible throughout the day.

Most customers have missed out the location of the small Casio instruction booklet, which is normally located right at the bottom of most Casio casing. 

Please find two images below fully illustrate the location of the Casio Instruction Booklet:

Alternatively, Click here to download a copy of CASIO watch manuals in PDF format.