From time to time when getting it cut, I tell whoever is doing the job to trim the top and don't leave anything long. I know I'm going bald. I don't want any comb-over hair waving around in the wind like a demented octopus. But, you know, you get tired of saying that and think you're being paranoid, so you stop. Then one windy day, you see the waving hairs.
So, instead of getting mad, I asked the next practitioner of the fine art of hair cuttery if that needs to be said every time. I was given an emphatic yes. Hair cutters don't know how we of the thinning hair crowd feel about our baring heads and so they err on the side of caution and cut long, leaving that dread comb over look.
If you don't want that, take it from the expert I asked, ASK each and every time for them not to leave you with comb-over hair. You'll be glad you did the next time the wind blows.