The primary difference between renewable and nonrenewable resources is how quickly natural processes can replenish or renew a resource. resources can’t be used up, like or sun, or are quickly replaced, like a or farm crop. resources have a concrete limit to them. Land is a good example because there is only so much land in the world. Other resources took millions of years to develop like and deposits and thus need to be seen as having a firm limit. Once they are used, they are not coming back.