Having done both a PPL(A) and PPL(H) I've flown with both good and bad instructors. How long they had been instructing didn't have that much to do with it; some newish instructors are first rate, and some experienced ones on such an ego trip that they refuse to treat students as individuals. Their enthusiasm or lack of it for the job was important, but even that wasn't the whole answer. I kept thinking I was getting better at deciding who was good and who wasn't, but it wasn't that easy; it's very hard to tell. Personality clashes in the air can be disastrous, and it's not worth sticking with someone you don't get on with. Other than that, if you aren't getting on, change. It's your money and your choice; always remember that.
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Whirly
To fly is human, to hover, divine.