The firm I used to work for was notoriously thrifty. My trap storage was limited to plastic tubs in the back of my Renault Kangoo!
Saying that old packets of silica gel seemed to keep excess moisture, inside the tubs, at bay.
The waxing depended on the location and the visible check on the condition of the trap. All the traps springs were waxed from day one. A liberal rub down, on the springs, was job #1. This wax was topped up where necessary while the traps were weathered outside. I wasn't too concerned with corrosion, during normal wear and tear, but I worked around a few salt mine