When designing parts that you know will later be updated or parts that have multiple configurations, pre-selecting your driven dimensions can save you a lot of time and hassle. However in versions prior to 2015 you could only make one dimension driven at a time. Not any more! In 2015 you can now "Ctrl" select as many dimensions as you wish, right click and select driven, making your sketch creation process faster and your model more robust.
By Jon Weston-Stanley
View the Video here