Have always used air. Usually put on 10-20 blades per week. Must have gotten Sloppy because blade flew off almost took off guys foot. He disengaged on driveway, blade was slowing then CLANG came flying out of rear of mower and whacked him in the foot. Will be Torquing after air from now on AND instructing to wait until Blades stop spinning on turf. Doubtful blade would have bounced and shot out if on turf. No he Will Not Sue. He's Fine, just Brusing. And No do not require Steel Toes. Too much Walking.