Here are a few simple pointers to keep in mind to help extend the life of outdoor wood projects. First, always err on the side of caution when building a deck. If you're not sure the structure is strong enough - over build. Keep in mind the golden rule when building outdoors. Always use hardware that is treated for exterior use.
Nothing contributes more to wood deterioration than improper hardware.
Untreated nails, bolts, and screws promote wood rot. And, remember to give water a path to run off the structure. Trapped moisture and debris start deteriorating wood quickly. Always look at the joinery and ask yourself if water can easily escape. Today, the cost of cedar or pressure treated wood is a serious budget issue.