There are several actions you can take to help extend the life of your air valve.  Here are the most important ones:

Maintain Clean and Dry Air

Supply air to the valve needs to be free of contamination.  Too much contamination can cause the air valve to stick, leading to valve failure.  Keeping the supply air dry is also very important.  Too much moisture in the air can also cause the valve to stick.

Lubrication

Non-lube service is offered by some air valve manufacturers, including MAC Valves, Inc., which means valve lubrication is not required to keep your valve running smoothly.  However, if lubrication is being supplied to your valve, then you need to consistently lubricate the valve to help keep it from sticking.  Always check with your air valve manufacturer before supplying lubrication to ensure compatibility with the rubber seals of the air valve.  Do not under any circumstance use solvent cleaners such as WD40 as a lubricant or a cleaner for your air valve.  Solvent cleaners dry and degrade air valve pre-lubricants and rubber seals.

Temperature

Extreme high and low temperatures can interfere with air valve performance.  Make sure that the temperature of the valve is kept between -17 and 48 degrees Celsius.  If the temperature of the environment does not fall within this range, then a special modification to the air valve may be needed for certain applications.

Preventative maintenance really comes down to the application and surrounding environment of the valve.