Keeping OSM updated and in sync with the real (changing) world is in my opinion one of the key challenges for OSM. Adding new roads and POIs is fun - keeping them up to date is less so!
Have you ever come across POIs or roads and made a mental note to yourself to check later in e.g. JOSM if they are on OSM and tagged correctly? I have, and unless I document in detail what I am seeing with photos, there is a good probability that I miss some essential details. Also with photos, I often have lots of photos recording stuff that is already correctly tagged in OSM. Thus the hit/miss ratio is becoming smaller and this will continue as OSM mature.
To help myself spotting differences between the OSM database and the real world I wrote a small Android app that can display OSM data for nearby objects. With this its easy and efficient to be on the lookout for OSM updates.
The app looks like this:
and it can be found on google Play: OSMfocus
I'm hoping this will be useful for others and that it will results in more OSM updates.