Pros with most / least switch of racket brand in his career?

My wild guess first, but not so sure (not counting after retiring from the atp main circut).....…

Verdasco (6)
Major, tecnifibre, dunlop, yonex, babolat, head....

Donald Young (5)
Head, tecnifibre, prince, dunlop, solinco.....

Federer (1)
Wilson

Michael Stich (1)
Fischer

Nadal (1)
Babolat

There should have been way more picks i guess......tell me more please

I was wrong for some cases, so just edited the above a bit.....thanks for people sharing