My personal hard drive capacity curve inflection point
It's not news that hard drives have been rapidly growing in capacity for, oh, the last two decades or more, all the while dropping in price. This affected everyone differently, but for me the inflection point where this made things really change was around 2006, or somewhat before it, and it changed in a really concrete way.
When I got a new machine in 2006, it was the first time that I wound up with enough hard drive space to swallow my old machine's data wholesale, without even having to think about it. In all of my prior machine transitions, I didn't have enough disk space to just take a full copy of the old machine and also fit everything I wanted into the new machine, so I wound up keeping the old machine running through an increasingly baroque series of lashups.
(At one point I had an Ultrix machine, an SGI Indy, and a Linux machine all running, each of them with some portion of my files. The resulting contortions were awkward and still ripple through to my current workstation environment.)
Part of this change was the steady march of ever cheaper consumer drives. But another part of it was that by 2006, consumer drive technology had finally reached the point where I was willing to trust it. All of my pre-2006 machines were built with SCSI drives, both because SCSI drives were more reliable and trustworthy than IDE drives and because IDE itself was kind of a beast to get running well on Linux; for a long time the received wisdom was that if you wanted good reliable performance, you paid extra for SCSI and accepted lower drive capacities. But by 2006, SATA and Linux support for it was far enough along that I could spec SATA drives without significant qualms and finally hop on the consumer drive bandwagon.
(It helped that SATA drives were cheap enough that I could spec two drives and then mirror them.)
Hard drive capacities have only gotten better since 2006, of course, and my home machine now has more disk space than I really have a good use for. But that 2006 machine was my personal Rubicon, the point where I finally had enough disk space that I could do things differently than I ever had before.