Why do Downloaded Google Maps expire after 29 days?
There hasn't been any info from Google as to why the maps expire in 30 days.  

A theory postulated in this Android SE site states


  ...I'd say it's highly likely that this time limit is related to contractual limitations at least in some areas. Kindof like how iTunes rentals expire, or Spotify Premium offline playlists expire: if there was no expiry date at all, then there's no difference between 'accessing' and effectively 'permanently buying for free/cheap'.


I also guess that Google wants to refresh the business list in the downloaded map data.  They charge businesses to advertise (not appear) in Maps and so they have an interest in keeping the downloaded data 'fresh'. &lt;-- my $0.02