I have 2 dogs who are 3 and 1 year old, neither dogs have been neutered, as I don't have any behavioural issues and I didn't want their coats to change or gain weight.
When got my first cocker I was going to have him neutered, but have since learnt alot and decided not to go ahead with it. The vets obviously want to avoid unwanted puppies, which I agree with, but my two are not mad for female dogs, unless one in season is waved under their nose. I haven't had any issues with roaming on this account!!
Vets also suggest it is better from a health perspective, however I have read veterinary articles that state in male dogs that it is less likely for an intact dog to get prostate cancer (which isn't immediately obvious), and testicle cancer isn't that common, and if it does occur then you are likely to spot it!
There is alot of information out there, so I would make sure you are certain you want to neuter before you go ahead, after all you can't put them back on, but can always have the operation done later if you feel it is necessary.