Same as what Dhama says.

  Besides that you need the hard drive space apparently.   I do the same.  One idea starts and evolves into something else until after  too many generations a final render happens.  So when it is all over "challenge scene file1" has no earthly connection to "challenge scene file 14"  and I just wonder "what was I thinking?" and delete them all.

Catarack eye surgery?  I Hope you are 100% soon.