How often are the images on google earth updated?

I'm trying to find out whether construction has been started on a place in my home town where I no longer live, and I'm wondering if the satellite images on Google Earth are a continuous stream of new images, or, if not (as I suspect they aren't), how often is the image of each place updated?|||Google says that they're all "less than three years old". I can date a few places in the US based on construction, and they all seem to be right around three years old. I'm sure there are areas that are quite new, but I don't know where they are off hand. They just sent a new satellite up, so new pictures are on their way.|||If you look in the bottom right hand corner of Google Earth it will tell you when the last date the pictures were taken.





GE doesn't really catalogue places that often, only the larger major cities.|||We have been using Google Earth for more than 3 yrs. In that time the standard aerial shot of our city (Melbourne - Australia) have not changed. The current Google Earth shows dirt tracks where freeways have been functional for more than 2 years etc. etc. We also updated to latest paid "Pro" version and it was no different.