Periodically, we get sewer gas smells from our kitchen sink [and cabinet]. We've had to replace our AAV four times in the last three years. It's located under the kitchen sink [in an island]. We've had several plumbers come out, and they all just scratch their heads. Any suggestions?

I'd scratch my head too! I have 2 houses, 5 AAV's, total of 17 years between both, never had to change an AAV. Are you using Studor AAV's?

Which brand and model are you using and what was the warranty? Did the plumber confirm the AAV was the source of the odor?

Yes, it's definitely the AAV because, once it is changed - the odor is immediately gone.
Not sure if this helps, but - there's always a lot of moisture inside the discarded unit. We've tried to let it dry out for a few months, to reuse them, but - they don't work then. So we just used new ones.They last between 9 months to a year.
As to which brand we buy. The plumbers have tried several, and the only one that seems to work is the Sure-Vent® Air Admittance Valves by Oatey®
[]Auto vents and automatic home sewer vents from FAMOUS PLUMBING SUPPLY (http://www.plumbingsupply.com/autovent.html#surevent). We need only the white top part of this unit, not the black base.

Yes, it's definitely the AAV because, once it is changed - the odor is immediately gone.
Not sure if this helps, but - there's always a lot of moisture inside the discarded unit. We've tried to let it dry out for a few months, to reuse them, but - they don't work then. So we just used new ones.They last between 9 months to a year.
As to which brand we buy. The plumbers have tried several, and the only one that seems to work is the Sure-Vent® Air Admittance Valves by Oatey®
[]Auto vents and automatic home sewer vents from FAMOUS PLUMBING SUPPLY (http://www.plumbingsupply.com/autovent.html#surevent). We need only the white top part of this unit, not the black base. Any suggestions?