Well, I don't claim to be professional I welded a wheel back on a donkey cart a few days ago and did reject a few rods I could have restarted except that I stucked em and 7018s like to slough off big chunks of flux when you unstick them. Just been given a few kg of Oerlikon Supercitos that I'm itching to try out. For non critical welds I think even a pro would happily use uncooked 7018s and restrike em. But sure, if someone is paying for the job why skimp on a few pence restarting a 7018?