1TB has been a sweet spot for me, I know my needs will grow over time but I update every 3-4 years so I think I'll be good for at least that long. I try to keep as little as I can on my laptop itself as I have servers and a Synology for media and the like. Also the portable "SSD"s from Samsung (like the T7) are really tiny and fast. I use one with Carbon Copy Cloner to backup my machine and have something I can boot from if my hardware were to die on me.