Similar to exterior mold, mold is more likely to emerge in warm and humid areas. That being said, rooms like bathrooms and basements are more prone to mold. To preemptively prevent mold, use paints that are mold resistant. Should you find mold on a wall in your home, you can clean it with a simple solution of one part bleach to four parts water. If the area is large, you may want to leave the cleaning to a professional.
Plan the schedule. Get a grip on the time it will take to bring the project to fruition. Plan for time to move furniture, wall prep, cut in, the painting itself, eating and breaks, and don't forget cleanup and bringing furniture back in. As you plan, err on the side of prudence. Unforeseen events will slow you down, so allow time for these. Remember, this is a multi-day project. Don't try to fit too much into a day. If you move faster than planned, great!
Most of a projects price is the cost of labor at $25 to $75 per hour. However, most contractors bid out based on the entire project which includes all work hours. Hourly rates are only useful if your pro asks to do the job as “time and materials.” However, be wary of this pricing structure, it usually shows the contractor is uncertain how long the project will take.