After committing to pay lots of money to have a contractor to tear their house apart and put it back together, homeowners pick some interesting items to save money on:

1. Portable toilets – Your contractor isn’t making money on it, and workers are entitled to a place to use the bathroom, so pay the monthly charge with a smile.  If you don’t like the portable, let the workers use a bathroom in the house.  I once visited a house where the owner and contractor couldn’t agree on paying for a toilet, so the workers used old 5-gallon paint pails, with snap-on lids.  When one of the workers left the project in a disagreement about something else, he kicked over all the pails.  It made a nasty mess, but I didn’t have a lot of sympathy for the owner or the contractor.  The cleanup was expensive.
2. Keys – pay the two bucks already and give your contractor a key to your house. If you really don’t trust him enough to give him the keys, you shouldn’t let him in your house, and it’s incredibly annoying and costly to track you down when he comes back from the supplier and you’ve gone out to lunch.
3. Power and water – Don’t follow your contractor’s workers around the house turning off the lights.  You can remind the contractor about it a couple of times, but workers really do have their hands full much of the time, and it’s just not safe to be fumbling in the dark for a light switch in an unfamiliar house, with an armful of tools and hardware.

It probably isn’t surprising that homeowners seize on these items: a remodeling project involves some lack of control by the owner, and these seem like simple ways to control costs and other aspects of the job.  But there are better ways to control the budget.