First off, try a data synchronisation tool like SyncBack SE. At just £23 it allows you to synchronise your changed files to a portable hard drive, FTP location or Network drive automatically. It can be triggered in the background as frequently as you like so if you are changing a lot of files regularly you can do an hourly snapshot. If you just want a daily backup though, you can set it to run when you plug in a drive or at a specific time of the day.
Your second option would be to go for an on-line back up service such as Carbonite. For those with a single machine (particularly a laptop) this type of install and forget system is well worth looking at. With unlimited data storage for just $49.95 per year it may take some time to do your initial back up but once it is done you will not even notice it is there.
So don't leave things to chance - back up your data and keep working.
