The reasons hobbyists scratchbuild may vary. Often a desired model is unavailable in kit form in the desired scale, or entirely non-existent. Sometimes the hobbyist may be dissatisfied with the accuracy or detail of kits that are available. Other times a hobbyist will opt to scratchbuild simply for the challenge. A hobbyist may also scratchbuild out of economy, as often the raw materials cost less than a packaged commercial kit.