On my Nexus 4, if the free space on the internal storage goes below 500MB the phone is unable to install/update apps (reports "There is insufficient space on the device")
From what I've found online, all the guides/forums etc. only suggest how to free up more space on the device, rather than suggest how to reduce this (to me, seemingly high) limit.
Is this because it's somehow hard coded into Google Play/Android? Or is it somehow possible to reduce this limit?