In Canada there is a requirement in law to fill out the aircraft log as soon as practical after each flight. When flying aircraft registered in other countries I record the flights for legal reasons.
Therefore should I need proof of any flight for any reason it can be found in the airplane log.
I must say though that I sometimes wish I had a personal log with pictures and comments, it would be really nice to have and I admire those who take the time to keep such a log.
However it is my opinion that not keeping a personal pilot log book has no bearing on being proessional, either in flying skills or safety.
Unless almost fifty years and in excess of 25,000 hours ( Transport Canada records )and still flying world wide for a living without an accident or incident or violation was just pure luck.
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The hardest thing about flying is knowing when to say no.