rule of thirds

When you’re chasing a big goal, you’re supposed to feel good a third of the time, okay a third of the time, and crappy a third of the time… and if the ratio is roughly in that range, then you’re doing fine.

Source: Bravey, Alexi Pappas

This probably applies to sustainable growth / “productive discomfort” in general. Corollaries: If you’re consistently feeling good, say, >50% of the time, you’re not pushing hard enough to grow. If you’re feeling crappy >50% of the time, you’re pushing too hard to be productive.

It may also by why small + consistent sessions are recommended over long but infrequent ones, whether that’s workouts or knowledge work like writing. In addition to volume + habit benefits, you get the full “range” of sessions. In 3 1H sessions you can have a good one, a tough one, and an okay one. In contrast, you’re unlikely to have a great + okay + tough combo in 1 3H session.

From Dan John in Never Let Go:

In a group of five workouts, I tend to have one great workout, the kind of workout that makes me think in just a few weeks I could be an Olympic champion, or maybe Mr. Olympia. Then, I have one workout that’s so awful the mere fact I continue to exist as a somewhat higher form of life is a miracle. Finally, the other three workouts are the punch-the-clock workouts: I go in, work out, and walk out. Most people experience this.

Not quite thirds, but directionally tracks.