System Restore reserves up to 12% of your hard drive space for storing information on these restore points. On my 40GB hard drive I found 4.2GB of space allocated to System Restore. When I checked the number of restore points, I found that there was one every day for the past two months, more than 60 restore points. That seemed to me to be excessive so I reduced the space allocated to System Restore to 2% (637MB). That decreased the number of restore points to 18 days, which I believe is more than adequate for the way I use this system. Since I also use a backup program, which copies my entire hard disk, I don't think I need all the restore data that WinXP sets aside. For minor problems, it is nice to be able to "roll back" the system to the condition it was in before a change was made.