All the fixtures are within 12 feet of the main roof vent.
We have a vent under the bathroom sink and kitchen sink. We had them installed two years ago, hoping they would solve the warmer weather plumbing issue.
Even the main pipe to the road sewer connection is less than 30 feet in length from the roof vent.
No issues with the pipes, like collapse, clogs, etc.
Only happens once the temps get around 70 degrees F.