ISAVEPERCENT system variable
Specifies the amount of wasted space tolerated in a drawing file expressed as a percentage of the total file size. If the estimate of wasted space exceeds the value set by ISAVEPERCENT, the next save will be a full save, which resets the wasted space estimate to 0. If set to zero, each save is a full save. Values between 0 and 100 are accepted.
0 to 100