Checking a painted mezuzah

Hi,

Normally, we require that mezuzot be checked twice in seven years. However, if a mezuzah undergoes something which could damage it, we check it immediately. Therefore, if a doorpost is painted, and the mezuzah was left on, we check the mezuzah to ensure that liquid did not enter and damage it.

(Rav Moshe Feinstein, Igrot Moshe Yoreh Deah 1:183)

Have a great day,
Mordechai