Builders are the best, had one a year or so back.
"Hi mate, I've been working on your neighbours roof and I notice you have some loose cement on your rige tiles, needs doing immediately of they could fall off".
Me: Thank you, I am aware.
"Yeah, but It'll come down if youdon't fix it soon"
Me: No it won't.
"Well, I've been a builder for a fair while, I suupose I don't know anywaying..."
Me: Obviously not, I value property as part of my job and am quite aware that a few stray bits of pointing do not mean the whole ridge needs to be lifted and repointed, no doubt having the felting underneath replaced. That and I had the roof checked by a mate in the business a week back when the neighbours said they were getting theirs repointed by the kind gentleman who informed them it needed doing...so I would check with teh neighbours as theirs doesn't need doing either.
Wandered off, swearing. He was planning to charge the elderly couple next door a cool £600 to repoint their roof which simply didn't need doing.