I'd be really interested to hear if anyone does try it out at a team-wide scale! For now, though, this is just a personal approach.
In terms of personal sustainability, I've found that (of course) there are some sprints where it just doesn't work out. Deadlines and other outside forces impact what stories are chosen, and sometimes I'll hit one or two, but not all three categories. In general, I think this is okay as long as it's not the norm. In work (and in life) sometimes urgent stuff just comes up and we work around it or buckle down and make do until it passes. Once that sprint is over, though, I get back on track. I assume (maybe optimistically) that this is what it would be like for a team, too – generally able to hit all 3, but with the odd sprint or two where that's just not possible due to stuff beyond their control.
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