You need to purchase the extended download service and that allows you 12 months of unlimited downloads. 

http://www.precisionmanuals.com/ProductCart/pc/viewCategories.asp?pageStyle=p&Pr...


What I do is download the installer, then save multiple copies of it on different hard drives with the registration codes saved in a text file.  If one hard drive crashes, you have it on another, and no need to download it again.