This depends. The cost can increase by 50% or more if you have a particularly rocky landscape. Our property was set on a steep gradient with lots of large boulders, some of which are the size of a couch. This affected the cost. However, if you live in an area where everybody has rocky terrain, it's unlikely that you will see an increase in the cost because of that; professionals who work in those areas have already taken that into account and padded their hourly rates to accommodate the local soil conditions.