Generally, you don't need to repot your indoor plants after buying. Since you are taking your plant into a different environment with different humidity, light, and a different watering schedule than the local store you bought it from, it will need time to adjust to these changes. Repotting your indoor plant can further stress it out and cause problems because it will need to adjust to a new pot on top of its new environment. However, there are a few exceptions to this, including if there's rootbound, a broken drainage system, brown leaves, not enough soil in the pot, etc.