To make the most of an investment in hard-surfaced plywood what precautions and practices should we take besides stripping the forms carefully and always oiling them before each reuse?
You are apparently inquiring about high density overlay plywood. It helps to use some kind of permanent framing system and it is good practice to reverse the plywood frequently to expose the opposite face. At the end of each job nails should be tightened and the forms repaired. One company has made it a practice to salvage heart pine 3-by 4 joists which they use in constructing high density overlay plywood forms when work is slack. The panels ought to be good for 50 to 200 uses, depending on the degree of care.