System Restore is one essential feature in Vista which have helped recover many of us from critical problems. There are lots of cases where System Restore has miserably failed.
Instead of going into pros and cons of System Restore, here we are talking about how often System Restore creates restore points in windows vista.
No matter how big your Harddisk is, System Restore may create too many restore points hogging the space on your precious Harddisk.
To know about it in depth along with procedure, visit here (Source)