A punitive approach to what could be unforseen and atypical delays may be a bad idea. I would suggest offering a bonus for the job being completed early rather than a penalty for it being delayed. If material is ordered, we can't make it arrive faster if something delays the shipment. We recently ordered a bathtub requested by a customer. It was promised by our supplier for a Wednesday delivery. Bad weather hit Texas and it just didn't leave the warehouse until the following Monday. It blew up our schedule for the project and it wasn't anyone's fault or mistake. If we have an employee critical to the project get sick or injured, we may not be able to get things done as originally scheduled. Jobs can get off schedule for a lot of reasons outside the contractor's control. Charging them for those things is likely to turn them away.
There are a wide range of costs associated with remodeling a bathroom, including size, the type of materials, its current condition, and the location. Homeonwers spend on average between $15,000 and $25,000 in their bathroom renovation. For example, the average cost of a 100 square foot master bathroom with tile walls and flooring, new fixtures, double vanity, and walk in shower with separate tub is around $20,000.