I've had some of the Rainbird 5000 in for 5 years. A factor to consider is your water. A high mineral content (lime) or algae from lakes will settle around the inside and cause the rotation to quite. Even the hot sun will disintegrate the plastic if above ground. But generally 6-8 years for professional and about the same for the box store one since they are about the same just labeled differently. Basically just watch them. The ones (1500 Series) with the blue filters tend to to plug quickly.
We all are merely gleaners from the masters who were here before us.