Make sure you know who is in your house that is supposed to be. Don't stand there and stare at the workers, but keep an eye on them and make sure that they don't go wandering off somewhere they shouldn't be. They might be looking for something to steal or for something that they can let someone else know about. If you have an alarm system, set it up for the parts of the house that no one should be in. If you have young children, keep them in one part of the house, and let them know that they can't go in the areas where the workers are or where you set up alarms.

If you have valuable possessions or something you might be afraid will get stolen, put those things in a safe. You can even rent a safe deposit box or a storage unit (make sure you get insurance and get a place that has heavy security) if you have many things.

If you have couches or tables that are in the way or near the place where you are working, move them. Put them in a bedroom for the day or in the garage if your work is going to take a few days. You don't want paint getting on them or a nail putting a gash in the furniture, so protect them and just move them. If you aren't doing too much work or aren't too worried, cover them with a plastic sheet. A cotton sheet might leak paint if paint spills on it. You can get them very cheap, even at the dollar store.

Plastic cover sheets are also great for floors. You don't want spots of paint or caulk to get on the floor and ruin the floor, so put the sheets all over the floor while you are painting.

If you have young children or pets, put up safety gates. Block off the area that has paint or is being worked on. You don't want a child running into the room and hurting themselves or spilling a bucket of paint all over the floor. Accidents happen so it is best to prepare for them.

You don't need to be paranoid that someone will steal things, most people are good people and won't steal something, but it is always a good idea to be precautious. You don't want something to happen that you could've avoided. Just keep an eye out and cover your things.