There's always some discussion in computer buying/building threads of how much space is 'enough.' My rule of thumb is to shoot for my current collection doubled plus 20%: (Cx2)x1.2

I still end up picking up external drives between builds, so it's safe to say my data collection doubles about every two years, give or take six months depending on what I'm doing at the time.

I built up maybe 3-5MB of files in high school in the '90s, which grew to about 80MB in college, and then stalled while I was an itinerant hippie for a few years. I bought my first PC in 2004 (and discovered DV within a month IIRC), and proceeded to outgrow first a 40GB then a 140GB then a 500GB hard drive. It took me maybe two years from there to break the 1TB barrier, and maybe two more to bump up against the 2TB ceiling. File sizes of all kinds get larger over time, and if you're an active techy sort you accumulate new projects with data archives running into the tens or hundreds of GB each (and that's without doing any 'real' coding/design).

How long have you been accumulating data? How often do you run out of space? Has anyone held steady for a while? Are you relying on the cloud/streaming, or physical media, or just not finding new things?