Different, more vintage way of finding interior painting expert, is to ask several of your friends. One of theme were making some renovation (other threads here) at house surely, perhaps he is ready to recommend someone? Because nice contractor is very rare, many of theme are doing nothing during their job, or sometimes you must to repaint after them. But there are a lot of trustful people out there, you just have to get some information about them. Never select first person you saw, better research him at start. Also, you could give your own offer in the local newspaper, maybe someone you know would declare his help? Of course, you can always do exterior painting on your own, but who has time for it? Less expensive will be to find a worker.
Exterior or Interior painting is not a piece of cake. When you wish to do it by yourself, make certain you have any skills and a lot of free time. Second option is to look for any well specialist. Just make certain it is someone reliable, if so, he will be able to finish his job within couple days, and you will admire the new view of your flat. If not, you could loose your money and mood, and perhaps you even must to finish after him. So beware.