I ONLY had my males castrated if there was a medical reason. Retained testicles would be one, but even then it's best to wait for the growth plates to close before castrating. Again if necessary. Two of my boys needed castration because of prostate problems in later life. I regretted having this done - they went very 'soft' and grew thicker coats. All the remaining zip had gone (even if they were elderly and had somewhat slowed down).
Vets want to do this surgery because it brings in income. 6 months is WAY too young to even be thinking about castration. And castration should never be seen as a cure-all for unwanted behaviour. That's down to training and if anybody expects an immediate cure, they will be disappointed. The only plus with castration is no unwanted puppies which shouldn't happen provided the dog is properly contained.
FWIW I wanted my Whippet spayed at around 6 months. Her then vet said wait, citing bone development issues and the potention for spay incontinence (not relevant with a male). So I waited until she was almost a year with no sign of a season starting, and asked him to go ahead.
Just to add - to my mind the Basset isn't a feisty breed, unlike the Terrier breeds, and when castrated, will become very 'soft' and lacking in any 'zip' they have. And it's sad with such a noble breed, to see one reduced to a fraction of what they should be, through being neutered - again unless it's needed for medical reasons.
