Answer:
So when will Google Earth/Maps update the imagery in my area?
You've checked Google Earth and imagery in a given area is older than 3 years. If you have the 'Status Bar' checked in view menu then the imagery date is shown in lower left of the map.
Sometimes Google Earth has newer imagery for a given area available in 'Historical Imagery' mode, which can be enabled in the View menu. Newer imagery may have more clouds, etc. and slightly older imagery is considered "better" by Google and used by default.
So you've checked and an area is older than 3 years and no newer imagery is available in historical imagery. Now you can report it via the data reporting form (listed in related links).
Individual requests get tabulated among millions of others so don't get disappointed if you don't get a response from Google nor see an update immediately.
In the meanwhile you should sign up for e-mail notification for updates in your areas of interest via the new 'Follow Your World' service (see related link below).