It depends on the resource. Some resources are non-renewable including fossil fuels-coal, oil and gas and important metals and minerals. Although fossil fuels were derived from decayed organic matter, they take so long to be replenished, these will eventually be depleted and will run out at some point in time. Although the minerals and metals on Earth represent a finite amount and can be depleted, recycling can return them to the supply to be reused. Biotic resources are those obtained from living things and include, forests, animals, plants and include the things made by them. As long as they are used sustainably, their supply can be maintained. Other resources like air and sunlight are found everywhere. Solar radiation will not run out in the foreseeable future, nor will geothermal energy.