I don’t know of any developer that couldn’t benefit from version control (aka revision control, aka source control).
I’ve used several different version control systems including StarTeam (one of my favorites) and Visual SourceSafe. Not everyone can afford a product like those, and sometimes it might be considered overkill.
If you need a free version control system, I highly recommend using Subversion in conjunction with TortoiseSVN. I’ve been using it for awhile now and on several different projects – it gets the job done, easily.
Subversion is a version control system intended to be a replacement for CVS in the open source community. Many open source projects can be disasters, but this is not one of them.
TortoiseSVN is a Subversion client, implemented as a windows shell extension. There’s no easier way to use Subversion that with TortoiseSVN. Again, all of this is free!
Do yourself a favor and check it out.