I also started with a luggable – but on a tighter budget – a Kaypro Z-80 based machine.
I can’t recall exactly when I got it but it got me through grad school par-time nights – in 1986 I got an MS in Computer Science from RPI.
I bought a Pascal complier so I could work from home instead of schlepping to the lab that was about a 30 minute drive.
I wrote my master’s thesis on it and printed it on a dot matrix printer and glued it to galley sheets and RPI bound it into a softcover book for a symposium put on by us students.
I used the spreadsheet it came with to calculate amortization tables when we were doing a re-fi – I think it took like 1/2 hour to calculate and print a 30 year amortization table.
After that a series of Intel PCs, then in 2010 a MacBook Pro, then in 2021 an M1 Mac Mini and a few months ago an M1 MacBook Air too.