if its a nylock type it can be used a few times, but if it comes off with out much resistance then id suggest replacing them, i think its a 30mm as far as i remember
That's not true. The whole point of a nylock nut is the nylock is deformed by the bolt causing a locking effect. Reusing the nut means it loses it's ability as a locking nut.
That's rubbish -been using the same nut over and over - torque'd up never been an issue - nylock type .