I do most of my school work on my school computer, but depending on the occasion, I sometimes take my work home to my desktop PC, and sometimes take my laptop to the library and I'm also constantly copying the files to my USB thumbdrive.

The result is that my files are scattered over 4 different locations, and it's impossible to keep all the work files in all these locations updated with the latest files. When I copy files from one location to another for backup, some files are newer on the source drive and some are newer on the destination drive. I have to look at each "would you like to overwrite" prompt and compare "last saved" times to make sure I'm not overwriting newer files with older ones. Is there a good solution that allows me to "synch" these folders so that only the newest files are automatically copied back and forth?