[spaghetti]

As Benny pointed out there's no rule of thumb.
Sore sinuses, inflamed middle ear, the eardrum and ear cavities made sticky or less elastic by mucus (as a consequence of inflammation), any post-traumatic deformity of nasal cavities: all of these factors will make equalization less effective and more painful, so taht you feel the need of equalizing more times, or simply abstain from going deeper.
How do I know?
This is what my doctor says about my medical case. I have them all: Sore sinuses, inflamed middle ear, the eardrum and ear cavities made sticky or less elastic by mucus (as a consequence of inflammation), post-traumatic deformity of nasal cavities.
I'm diving 25 meters with 3 Valsalva and a couple of Marcante-Odaglia eq's. More pain in cold water!