In my humble opinion, I, generally, follow the vets' recommendations. Are they going to work to make money? Sure! We all go to work to make money.
I really like my current vet and heed his advice. I've sent a co-worker to him, who has referred others to him, even though he's on the expensive side. My co-worker's partner is a nurse, and she REALLY liked my vet!
Fortunately, for me, I've had nothing but good luck with my Dobes.
I sell cars, and I really suggest an extended warranty, for that piece of crap you chose to buy from me!