I would venture to say that a vet visit is also predicated on who you purchased your snake from. If the purchase was made at a pet store, I would make an appt with the vet and take a fecal sample as well.
I purchased my snakes from three breeders who are reputable, respect their animals enough to maintain excellent health, and in whom I place my trust; therefore I have not felt the need to go to the vet.
That said, I do have an 8 year long relationship with our vet and she is well aware of my snakes and standing at the ready should a problem occur.
May I ask why you are inquiring? Are you getting that little unnerving feeling that you might feel more settled if you were to get your snake a clean bill of health? If this be the case, by all means, take your snake to the vet!