If oil supplies get exhausted, then it would affect our life style in a very serious way. Without petrol, diesel, coal , oils , etc. we can't live life easily. We can't use vehicles and we'll have no electricity. It would be a very difficult situation. We can not imagine our lives without oil supplies. It is necessary to preserve and conserve our natural resources, especially non-renewable resources. We can always use renewable resources in place of non-renewable resource. So, we shouldn't waste precious oils and we should be eco-friendly by using renewable resources.
Hope I helped :)