As you work with dimensions, you might find that you'll make adjustments to the dimension style little by little, until you set up a style just the way you want. Once you've reached that point, you probably won't change your dimension styles often. You can then save your dimension style to a file using Express Tools, which are a set of optional plugin tools that you can add to AutoCAD 2008 (not 2008 LT), or you can add them to your most frequently used template file so the styles are available at all times.