Good question. The answer nine times out of ten is yes. Small jobs such as painting, minor changes of bathroom and kitchen fixtures will not require a permit. However if you plan on doing anything electrical, plumbing, HVAC, structural, landscaping, etc a permit is normally required. It also can save you money in the long run by avoiding costly fines, and stop work orders. When you go to sell your property, you will be able to disclose to the potential buyer whether not you pulled proper permits. There can also be insurance problems when collecting on fire damage when a permit was not used to do the renovations. Better safe than sorry I say.