You have a medium save window, which means that you have a 4- to 6-hour block of time available daily with no system activity. Use this strategy if you find that you do not have a long-enough save window to use a simple save strategy.
Perhaps you run large batch jobs on your system at night. Or, you have very large files that take a long time to save. If this is the case, you might need to develop a medium save strategy, which means that the complexity for saving and for recovery is medium.
When developing a medium save strategy, apply this principle: the more often it changes, the more often you should save it. You just need to be more detailed in evaluating how often things change than when you use a simple strategy.
Several techniques are available to use in a medium save strategy. You can use one of them or a combination: