Safest way to ensure that everything is fair is to get it ALL in writing , signed by both parties. Specify each item that needs repair. Also, BUY the paint YOURSELF. That way, there is no incentive to water it down, and you KNOW that you are getting the grade/quality you actually purchased. Don't be penny wise and pound foolish; if you are paying to hire a painter, buy the best paint that you can afford, to ensure maximum life of this home improvement.
Inspect the surface area for holes, cracks or other problems and apply acrylic caulk to fill them in. Use a putty knife to smooth out the caulk and remove any excess to prevent bumps. For particularly thin or narrow crevices, you may have to use your finger to smooth out the caulk. Caulk contracts and shrinks, so apply a second layer once it's dried.
My painter franchisee, who I got from Angie's List, must have found some shmucks on the corner to paint my house. I specifically said I wanted stain. First my house was painted the wrong color, Then it was painted with LATEX paint- not stain. Estimates to 'undo' the damage is around $10,000 and its not a guarantee that it will work. The work is at best amateurish. Many underpainted or not painted spots, drips, etc. They did the entire outside (scraping?, priming? caulking?, painting), cleaned up and left within the time I left for work and came home. There were thee of them (my neighbor told me) This was two years ago and I am still upset. Can't be fixed.
Thorough preparation is essential to ensure a good finish. Contractors might have to fill cracks or holes and remove old paint if it is badly worn, peeling or flaking. They remove all paint and apply a suitable primer to the bare surface. If the existing paint is in reasonable condition, they clean it and rub it with abrasive material to provide a key for the new paint. On new surfaces, such as bare wood or fresh plaster, they apply a suitable seal, followed by a primer coat.