Halocho #1277 - Mezuza checking

The Torah commands us to put a Mezuza on all our doorposts except for washrooms.

The Mezuza needs to be affixed to the top third of the doorpost - but not in the top 1 Tefach (~9 cm; 3.5"). 

Every Mezuza needs to be checked twice in seven years. 

A Mezuza on public buildings only needs to be checked twice in 50 years. 

Source: Kitzur Shulchan Aruch 11:5,17,25

Some have the custom of checking their Mezuzot in Adar-I; this is slightly more frequent than twice in seven years, but it's easy to remember.

- Danny
Sunday, 2 Adar-I 5774