For years I've only shot 24-exp rolls in my half-frame cameras. With careful loading, I typically fit 55 negs with the Pen F and 52 negs with the Pen S. That's already PLENTY of negs to scan and postprocess. (Also I'm not a big film burner, it often takes me months to shoot that many pics. A 36-load would take over a year!)
I've mostly been shooting Film Photography Project's "X2" aka Kodak Double-X/Eastman 5222. I bought a few rolls earlier this year and recently finished the first one in the Pen S... and discovered that it was clearly LONGER than usual 24s - I got 62 negs! Mind you, I'm not complaining, it's even more economical than usual!