Not sure if it's quite what you want, and it's prehistoric in design, but I have a set of batchfiles that copy my key documents, pix, etc to the "backup" external hard drive. They create a new folder each time with a name that includes the date - so I can delete the intermediate ones.
It's optional what "keep" routine you operate, but "last five days, last five Saturdays before that, last five month-ends before that" sort of idea works well.
Windows Task Scheduler is set up to run it. Deleting old files is manual.
Here's the bones of the batchfile format:
@ECHO Keef's Backer-Upper to the external drive...
xcopy C:\Docume~1\Keithj~1\MyDocu~1\*.* S:\MainBU%date:~6,4%%date:~3,2%%date:~0,2%\Doc\*.* /C /D /S /Y
@ECHO All done
That's easily editable to suit requirements. Not as elegant as the proprietary solutions, but it's worked well for me for a very long time.