For most starts, I call it before starting, as well as having a good look round. My Club SOP is to look only, this is my only exception, but I still call in the Club aircraft when away from Base - our ASP is well sanitised, but you never know at other airfields, and especially on farm strips).
Call it belt and braces if you like, but if it prevents just one person from being hit with a prop, then it's worthwhile.
I remember some years ago at Gloucester, I overheard a C150 instructor ridiculing his student, telling him it was Naff to call 'Clear Prop' and it made the both of them look stupid. He added that real pilots didn't do it as they didn't need to.
I think all the instructor achieved that day was wanton destruction of good airmanship. I took great delight, some 30 mins later when I was starting a Spitfire as the pair were walking back to their machine. The look on the instructors face was a real picture, when he heard a loud: 'Clear Prop' just before the Merlin coughed into life...........
Before starting, have a good look, call a good loud: 'clear prop', then hit the starter in the knowledge that you have done everything possible to prevent someone being hit by your prop - you know it makes sense.
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