The free version of Google Earth has an outdated map of the world from about 2005. The paid version of Google Earth is updated regularly.
The images in Google Earth (and Google Maps) are updated on a continuous basis. It's hard to say exactly when an area will be updated because some areas may be updated more frequently than others. Google provides KML feeds showing what areas have been updated in a given update. Google also provides a notification service you can signup to alert you when a given area is updated. For details see the related question.
New Google Earth satellite imagery is added approximately every 2 weeks or a twice a month. Street View imagery is updated on its own schedule. The same imagery that is added for Google Earth is available to Google Maps as well.
Google Earth imagery is updated every 2-3 weeks. See related question for more details.
Each photograph is updated about every 2 years so you just have to wait.
Google updates its imagery every 2-3 weeks. You can see what has been updated in each imagery update in the related links below.
Imagery in Google Earth gets updated world-wide every 2-3 weeks but the same area may not be updated for six months or 3 years. What gets updated depends on the demand for a given area. Everyone wants their area updated first and the world is a large place -- major cities naturally have high demand so they'll usually be updated more frequently than a rural area.
Well, Google Earth is a very popular company to view our world, but there's one called " Microsoft Virtual Earth " as I know of. It isn't as great and updated as Google Earth is, but it is another company. Also, unlike Google Earth, you don't have to download Microsoft Virtual Earth.
Google tries to keep imagery less than 3 years so if the imagery where your house is located is older then you can report it to Google. As of 2012, 75% of the world can see their house and neighborhood in high-resolution on Google Earth and Google Maps. In the meanwhile you can subscribe to receive notification whenever Google does update imagery in home area. See related links below.
The aerial, satellite, and Street View imagery in Google Earth is not real-time (or live). But there is also a webcam layer integrated into Google Earth (enabled in Gallery layer) that can show "live" scenes at selected locations.
Google never lets on when it will update an area. You can, however, subscribe to e-mail notifications via Google's new 'Follow Your World' app to receive e-mail when the area is updated. If enough people subscribe to a given area then Google can use that to prioritize which areas get updated.
Google Earth software is updated several times a year with major release (e.g., 5.1 -> 5.2 -> 6.0) approximately once a year. An incremental Google Earth version update increases the minor version numbers (E.g., 6.0.0.1735 -> 6.0.1.2032 -> 6.0.2.2074). Google Earth content (imagery and layers) are constantly updated and released usually every 2-3 weeks but any particular area might not get an update for 1-3 years. The content is stored in google's databases and served from their public map servers.