Purge

I have been in the business since 1996. I have about 3TB worth of images total. Approximately 1TB of this total are images from 1996-2000 (kids, weddings etc) and most of those people are either grown up or sadly, deceased by now. I have contacted all of the previous clients to no avail (I wanted to just give them the files since I don't need them). So now, I have these old files just taking up space on Smugmug (which isn't an issue, until they drop the unlimited option) and my hard drives (which IS an issue...hard drives are cheap but I don't want 100 of them floating around).

-->My question to you other professionals, when do you purge old files? I have a colleague that purges after only one year. He assumes all the print sales are going to be completed in the first 6 months. He will offer them to the client for a flat fee, if they don't want them, delete. I just cant bring myself to do it, cause murphys law is the rule around here (just as soon as I hit delete I will get a call from the client 'do you have my images from 8 years ago, blah blah').

Thanks for any advice!