How often are stud dog owners testing their studs? Once a year, every 6mos, or on the same schedule as they'd require the bitch (w/in "x" number of days of breeding)?

I usually do it about once a year. If not often might wait until someone called to use him.

2x yearly for brucellosis screening

It's pretty easy for me to do, but I have my dogs tested every 6 months, if they are going off of my property for shows, field work, etc. I have also started getting complete semen analyses and bloodwork done every 6 months (beyond just my own microscopic evals)- I am pretty proactive with regard to testing though- I want to catch any abnormalities early on, and it helps ensure the dog won't be the reason behind a breeding that doesn't "take." It helps with my peace of mind (I'm a worrier). ;)