collector only works 'while using the app' or, while the app is open. it'd be great if you could lock the screen on your phone and have your location streaming while the phone is in your pocket.
we use collector to record tracks where we are spraying herbicide for invasive species management. if the phone goes in your pocket while the app is open, it's subject to having buttons pushed and may result in a 'butt-dialing'. if you have to hold the phone in one hand and keep the screen from locking or going into sleep mode, then not only is the phone consuming more of the battery but, it's subjecting the device to sunlight and heat — both of which are bad for the device.
the arcGis app uses location services 'always' and it seems that it'd be easy enough to include this option within collector. while i could use the arcGis app to collect features, i'd prefer that our employees only have access to the data that is available to them through collector app.
Moderators note: This idea has been marked as a duplicate of Option to have Location Tracking on when App is in background. Please consider voting on this idea.