There are many things to considern when looking for where to stay in Playa del Carmen, and the best places such as condos and houses for rent for vacation, long term and short term. It doesn't matter how long you are staying, as long as it's at least 3 days, staying at a vacation rental rather than a Hotel brings many benefits.
One of the most important ones is that of having more privacy and a kitchen. Being able to get groceries and cook will dramatically reduce costs the longer you stay. You will also meet neighbors and get a better sense of the culture and get a more local flavor of the town. Here is more information about the benefits of a private condo vacation rental in Playa.