A few things can be done.
1) Proper ESD control - most of the time ESD will damage internal IC's but not necessarily flat out kill it. This leads to future failures when heat+current is ran through that damaged circuit over time. Use a grounded work area, wrist strap, and store components in ESD safe material.
2) Proper storage. As mentioned, store components in an ESD safe bag. Store them flat with the least amount of stress on the board; never stack components directly. (I use motherboard size boxes with foam on the bottom for each component) Broken solder joints and traces can occur over time with boards flexing. Keep the storage area environmentally controlled. This will prevent mold growth, oxidation, corrosion, etc. If stored in a basement, run a dehumidifier or central AC to keep the humidity lowered. Utilize shelving to keep boards or computers off the ground in case a flood happens.
3) Maintenance of boards. Replace electrolytic capacitors every 10-15 years. Some capacitors last longer than others, some puke their electrolyte onto the board, and some just don't last as long as the manufacturer claims. It also helps to energize components every 6 months or so to reform the capacitors. Remove batteries from boards for long term storage. Apply something like DeoxIT to connectors, sockets, and gold fingers - this will provide a protective barrier as well.
4) Ensure your test equipment is also up to par. Utilize power supplies with good voltages and low ripple. Invest in a multimeter. Check for shorts on components before powering them on.