Good thread Dave. The bit about both systems needing to be reliable and
trusted is the key point most discussions of this miss.
One thing I'd add from running my own GTD system across personal and
work contexts for years: the bottleneck usually isn't the systems being
separate. It's the gap between them. The capture-and-transfer ritual you
described, where you write a personal note on a card at work and input
it into your personal system at lunch or that evening, is the part most
people skip. And the moment they skip it, both systems become
untrustworthy because the cross-context items leak.
So the question I'd ask anyone in this situation isn't "one system or
two" but "do you have the discipline to start a ritual for moving things between
them." If yes, two systems works. If no, even one system breaks because
the cross-context capture is what fails.
Having the discipline to do the transfer is what makes the two-system approach work!
