The care that you take on your drysuit depends largely on how often you are diving the suit.
A. The suit needs to be rinsed on a regular basis (at the end of each days diving)
B. The suit should have the zipper waxed on a regular basis (I find my suit needs it after every 3-4 dives -this sometimes depends on the type of wax used).
C. the Seals should have seal saver applied every few dives as well (as needed - most suits usually need it every 6-8 dives)
D. The suit should be transported with the zipper closed, and stored with the zipper open. If there is a possibility that the zipper could "fold" (something fall on top of it etc.) you want the zipper to be closed. If the zipper is not done up, and something fell on it - it could compromise the zipper.
E. The suit should be rolled (if you are rolling it) with the zipper on the outside of the roll. Again rolling or folding a suit where the zipper could be folded in half is not good for the zipper (whether it is done up or not). This will simply prolong the life of the zipper.
F. Store the suit in a cool, dry spot away from direct sunlight.
Hope that helps!
Until the next Dive,
Tyler