You can use a duplicate copy of a Bid to perform "What If" scenarios without affecting the original Bid.
You can duplicate multiple Bids in the same database - just hold down <Ctrl> or <Shift> and click on the Bids to duplicate, then hit the duplicate button.
Some estimators setup a main template Bid that has all Conditions, Areas, Subs, etc. created, and duplicate this template Bid for each new job. Then you just customize the duplicate copy to meet the current job's requirements. Duplicating this 'template' job makes it easy for an estimator to start a new project using approved preferences and Conditions.