Local data retention: What and for how long?

Once data is submitted to WebObs, What data do you keep locally, and for how long

All my images are through AAVSOnet, and I have not downloaded any images, only analyzing them online using VPhot. I've kept TA and TA Reports locally for all observations submitted. Is there a "standard" or "best practices" on whether this is the best approach or whether local storage is even necessary given that I can't get to the images after some period of time. What do others do??

Clear Skies,

Peter