Not all paints are created equal though- different types of paints have different drying times. For oil based paints, let the walls dry for at least 24-hours before re-applying. However, if you are using a latex based paint you can begin your second coat in 4-6 hours.
Ask about certifications and training the company and its employees have. Many painting companies hold memberships with the Painting and Decorating Contractors of America, which provides continuing education programs for its members. If you have an older home, built before 1978, look for a painting contractor that is EPA Lead-Safe Certified.

Some house painters like to take on many jobs at once to make more money. They hire sub-contractors to actually do the work while they go out and find more jobs. It’s a situation you want to avoid. Instead choose a painter who actually does the work or who has full-time employees do the work.
Painters charge $1 to $3 per square foot to paint a room or interior of a house. The average cost to paint a room is $350 to $850, and the cost to paint a home interior is $1,200 to $3,900. Labor costs alone account for 70% to 85% of your total paint job. Interior Painting Cost Per Square Foot Calculator Measure Cost Per Square Foot Coverage Area $1 – $3 Floor Space $3 – $7 Interior Painting Cost Room Average Cost Interior Door $75 – $150 Bedroom $350 – $850 Master Bedroom $650 – $1,400 Bathroom $150 – $400 Kitchen $150 – $250 Living Room $600 – $2,000 Apartment / Condo $900 – $3,000 1,500 SF House $1,300 – $4,400 2,000 SF House $1,600 – $5,600 2,500 SF House $1,800 – $6,300