Depending on the size of your drive 2GB may not be sufficient on a resource stance.

20% is usually a good figure:

500GB = 100GB
400GB = 80GB
300GB = 60GB
250GB = 50GB
200GB = 40GB
160GB = 32GB
120GB = 24GB
80GB = 16GB
60GB = 12GB
40GB = 8GB
20GB = 4GB
8GB = 1.6GB

Follow this rule and you'll never be without free space.

Good Luck!