The question about the right size is essential for most users. For the average user, it is safe with 15.4 inch display models. These units are also found in the lowest price classes, have reasonable display sizes and are comfortable to work with at home. At the same time, they are still light enough to transport from time to time. Someone who looks for a desktop replacement laptop and the notebook is relative stationary, one should look for a 17 inch laptop, which is better for your eyes. The larger the display, the more power that is needed and the battery life is shorter. For an especially mobile user, one should look for a 14.1 inch variety, a subnotebook with 13.3 inch screen or smaller like the ultra mobile PCs, (UMPCs). Overall, one must account that the smaller the screen, the more it will cost. An exception is a subnotebook, which different manufacturers offer, with screen sizes between 7-10 inches; those can cost under 300 Euros.