> the weekends are a pretty good picture of how we'd behave at retirement.

I think this depends on how one’s current job is affecting them.

If you’re near burnout or just work in a very stressful environment, the weekends are more about recovery from the week and might not be a good predictor of future choices when not stressed/burnt out.

Basing this comment mostly on personal experience since I’ve had both productive weekends and lazy/lost weekends and it generally depends on how the current job is going.