How does everyone handle situations where things go wrong at the last minute, such as a model not arriving which forces cancellation of the shoot? What if the client arranged that element which went wrong? Studios and stylists and prop rental outlets will still expect to be paid. It can quickly become an expensive mess.
Or what if the weather forces cancellation of a shoot? I've heard of weather insurance, although I've never used it. Is it recommended or is there a better way?
Make it plain to the client what the costs are and organize the contract to cover your costs if your client lets you down.
Take a non-returnable deposit in advance (wedding photographers get away with it)
Call your sister-in-law, niece, (yes, OK, great-niece) or regular model as substitute model.