Homes of between 3,000 & 5,000 square feet are in our Medium sized group. They generally have 1 or 2 analog phone lines and between 8-16 phones. Phones are normally installed in the kitchen, family room, 4-5 bedrooms, master bath, laundry room, gym and garage. There are usually at least 1 or 2 wireless phones for the inside of the home and possibly the pool or cabana area. Medium size systems tend to lean toward the KX-TDA50. However, if there is any need for VoIP - either Outside Lines or Off-Premise Extension (such as a vacation home), the better choice would be the NCP500.