In the late 1970s, while working for a daily newspaper, I had no cameras with working light meters and I got to be pretty good at guessing exposures. But we used only Tri-X at the time and the latitude was enough to carry me through when the exposures were off. And many of the places I had assignments were familiar since we were there over and over again--city hall, athletic stadiums, jails, hospitals, etc. On my own time, I used the various Kodachrome films but I used a handheld meter. No room for guessing with Kodachrome. I was pretty good at guessing but I wanted to be sure when I used Kodachrome.
I'm quite a bit younger than you, but my cohort in journalism school was one of the last to still be taught on film. I had a very old-school professor that insisted we shoot nothing but HP5/TX, learn exposure with a gray card, and later guess exposure the rest of the time. I got to be...okay with it. I also made it hard on myself shooting my final project on medium format and Neopan...
It was a big shock going from that run-and-gun style, to learning LF and zone system in grad school. Nowadays it's a little of both--finessing sunny 16 on small format ( I never trust 'A' mode on my M262), but since I shoot a lot of transparencies on larger formats, a meter is necessary, and not at all slowing me down considering I photograph architecture mostly.
The Bronica kit I inherited came with a metered CW/spot prism, but it was out of commission for a long time. I ended up getting a Sekonic Multimaster with incident and 5º spot mode—not quite as precise as a traditional 1º but hugely more versatile; the iOS metering apps just weren't working accurately for me, but that's likely because I have a very old, and very slow, phone.
Judicious use of epoxy got the metered prism back in service, but I honestly prefer a WLF and external metering most of the time.
To the OP: The Gossen DigiSix and Sekonic TwinMate are both fairly popular clip-on meters, depending if you want digital or needle display, but both require using a calculator dial. I don't know if they still make it, but the Voigtlander meters were great, with a pretty intuitive ISO/shutter/aperture dial system.