Here I let it use as much as it likes. With today's huge drives there is little need to limit this.
Bob
I'm running Windows 7 Home Premium on a Dell Inspiron N7010. My system restore points are continuously deleting somehow. I have created restore points manually and I have seen the occasional restore point created from system updates. I will then check back after about an hour or so and the restore point is no longer there! I found that my volume shadow copy service was stopped - I restarted it and set it to auto start. I have system protection set to restore system settings and previous versions of files and have 1.46GB set aside for restore points. I have had it set as high as 2.93GB. I have my laptop set to go to sleep when I close the lid, so I'm wondering if that may be an issue.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic