My DS got a diagnosis of mild tourettes when he was 6. He got a diagnosis because he has had motor and vocal tics (vocal tics include throat clearing, sniffing) for two years or more.
He still might grow out of them. They are not cause by anxiety but are worse if he's tired.
As pp has said, his wax and wane, sometimes they are awful, especially the multiple tics which involve a sequence of movements, for example, jerking his head back, pulling his shoulders down, bringing his hands up.
He can feel trapped by them at times and has callouses on his thumbs where he rubs them repeatedly.
We were told to not encourage him to hold or change his tics because he can't control them (well he can try for short periods but it's exhausting).
I sometimes give him massages to relieve his neck and occasionally pain relief if he gets sore because of one of his tics.
Ds2 is 6 and has ASD has some shocking tics at the moment but we haven't pursued a diagnosis for him as there's too much else going on.
My dh had tics as a child and didn't out grow them but his are very mild and almost unnoticeable.