Is $2,275 to stain a wooden privacy fence a fair price?

We had a wooden privacy fence installed about two months ago. We are looking at treating the fence to improve the life span as much as possible. I am looking for product and process recommendations. From what I have read so far, cleaning and pretreating the fence before staining and sealing is important for the best results. Is there an advantage to staining? Or will just using a sealer work? I have a pressure washer and paint sprayer available to use for this project. The size of the fence is roughly 650'. If I do it, I plan on doing this in sections over several weekends. Does it more sense just to let them do it?