There are many reasons to buy a new rig. It may be a young man (or woman) going into business with their first rig. It may be an established drilling business looking to expand or branch out, such as a plumbing or well service business that needs a rig to service their customers. It may be an established drilling business that wants to go into another line of drilling, such as geothermal or geotechnical drilling. It may be the need to upgrade to keep up with technology.
All of these needs require a different rig, and the selection process is different. For instance, if you are upgrading your fleet to keep up with the latest technology, you are looking for all the bells and whistles. A new, rather than used rig, may be what you need. There are many new, latest generation rigs on the market. They may be sold for several reasons. The owner may have bit off more than he can chew. Or his scope of work has changed, or he decides that the newest generation of rig is not productive enough to justify its cost.