The team-level taxonomy guide on this shelf covers designing categories that inform a specific decision rather than exhaustively describing every kind of work. The same principle applies, with a slightly different set of pressures, to a personal taxonomy — the categories one person uses to track their own time, without the team-reporting or billing requirements that shape a professional system.

The specific failure mode of a personal taxonomy

A personal time-tracking system built during an ambitious, organized moment — often at the start of a new year or after reading a book on the subject — tends to start with far more categories than the ones described in the team-taxonomy guide, because a personal system has no other stakeholder to push back on unnecessary complexity. Without a manager or a billing requirement forcing simplicity, a personal taxonomy tends to grow until it collapses under its own detail, usually within a few weeks, once the initial motivation that justified the extra categorization effort fades.

The most durable personal taxonomies tend to converge, after some trial and error, on a small number of categories that map to a genuine ongoing question the person actually cares about answering — how much time goes to deep, focused work versus reactive tasks, for instance, or how the week's actual hours compare to the plan, connecting to the plan-versus-log guide on this shelf — rather than an exhaustive breakdown of every activity performed. For a practical software example related to self-reporting bias, read the full guide.

Letting the taxonomy evolve instead of designing it once

A personal taxonomy is easier to get right through iteration than through upfront design, precisely because the question a person actually cares about tracking often only becomes clear after a few weeks of rough, imperfect logging reveals what's actually interesting or surprising in the data. Starting with a deliberately minimal set of categories and adding a new one only when a specific recurring activity keeps getting awkwardly forced into an existing category — rather than trying to anticipate every category needed from the start — tends to produce a system that fits the person's actual life rather than a generic template.

What a lasting personal taxonomy is ultimately for

The point of a personal time-tracking taxonomy isn't completeness — a fully accurate account of every minute of a life is neither achievable nor useful — it's giving a small number of ongoing, personally meaningful questions a reliable way to get answered over months, in a form simple enough to actually maintain that long. A taxonomy that a person is still using after six months, even a minimal one, has produced more real insight than an elaborate one abandoned after three weeks.

A personal taxonomy succeeds by being small enough to survive a busy month, not by being detailed enough to describe every minute of it. Completeness and durability are usually in direct tension with each other.

This closes the loop with the categories-that-help guide on this shelf: the same discipline that keeps a team's taxonomy useful — fewer categories, chosen for a specific question — applies just as much, and arguably more, to a personal system with no external pressure to keep it simple. For additional background on this subject, consult RescueTime.