I need to deploy several instances of my app in a smartwatch. We will then give the watches to some users and we won't have access to the devices for 3 months. We won't publish the app in the play store, for which I mean, we will manually deploy the app into each of the devices (either using the IDE or distributing a compiled apk).
I remember a couple of months back, I developed an application for iOS and I noticed that after two days of inactivity I was not able to keep using the app because of "security". I just wanted to know if there is any similar restriction in Android which could prevent me from having an app running for several months without rebuilding it and re-installing it.
As long as the app is packaged and signed correctly for your method of direct installation, the app should install and continue to run on any Android device uninterrupted without any problems.