Here are some reasons you may want to change your cluttered desktop habit:
1. Slower Computer. If you have an older computer, it may slow down your computer because those little icon images (although very small) are stored in your RAM. They do use up your memory space. If you do not have much RAM, the overuse of the desktop could slow down your computer. Not so much a problem with newer computer with more RAM, but there are other reasons, too.
2. No file protection. PC World wrote that files on the desktop are affected by System Restore, which can result in unexpected file disappearances.
3. No file backups. Many file backup programs ignore desktop files by default. Hopefully, the backup program you use will let you modify settings to include the desktop, but if not, you could accidentally lose your important desktop files and folders if you rely on a backup program which does not include the desktop.
Read More:
The pros and cons (mostly cons) of saving files to the desktop (Windows)
http://www.pcworld.com/article/2110003/the-pros-and-cons-mostly-cons-of-saving-files-to-the-desktop.html
The Downside to Desktop Storage (Windows)
http://www.makeuseof.com/tag/3-better-ways-store-files-desktop/
Why You Shouldn’t Store Files on the Desktop (Mac)
http://computers.tutsplus.com/tutorials/why-you-shouldnt-store-files-on-the-desktop--cms-21721