Once the brick is painted it is difficult to remove all the paint. The paint absorbs into the brick mortar and does not easily come off. Painting brick is much more common because brick colors often date the house and may need color updating. The vision and value of the whole appearance of the house, painted or not, is the best answer. Once the brick has been painted – I suggest that you remain open to painting the brick. If it had never been painted I would advise you try not to paint the brick. I suggest power washing the brick first, see how clean the brick and mortar gets, and then decide whether to paint or not. I also suggest that you schedule painting the brick into your preliminary plans. I think power washing the brick will be only partially successful.