The long session myth: why 10 minutes is enough
TL;DR
Across 267 tracked sessions, 62% last under 10 minutes. Long sessions (>1h) account for only 15% of the total. The micro-session is the real productive pattern — not tool underuse.
267 coding agent sessions tracked since December 2025 on a Symfony/TypeScript project. The duration distribution:
< 10 min 165 sessions (62%)
10 - 60 min 61 sessions (23%)
1 - 4 h 21 sessions (8%)
> 4 h 20 sessions (7%)Most agentic work happens in micro-sessions. Not 2-hour marathons with the agent — short, focused interactions, then back to the code.
What happens in a 10-minute session
One precise question, one answer, maybe one adjustment. Typical examples:
“Why does this PHPUnit test fail with a 500 on this endpoint?” — the agent reads the test, the controller, identifies the missing mock. 3 minutes.
“Generate fixtures for this entity with its relationships.” — the agent produces the file, you check, adjust one field. 5 minutes.
“Refactor this switch to a strategy pattern following project conventions.” — the agent reads the existing code, the AGENTS.md conventions, produces the refactoring. 8 minutes.
These are complete deliverables. Not unfinished sessions.
Why long sessions are an anti-pattern
Beyond 30-40 exchanges, context rot degrades response quality. Early instructions lose their influence. The agent starts contradicting its own earlier decisions.
The 20 sessions over 4 hours in the data are almost all “catch-all” sessions — chaining unrelated tasks, drifting debugging, exploration without clear goals. The outcome/time ratio on these sessions is significantly lower.
The reflex to build
The right question isn’t “how to make sessions last longer” but “can I break this into a 10-minute session?”
If the answer is no — if the task genuinely requires broad context and sustained reasoning — then a long session is justified. That’s 15% of cases. For the remaining 85%, the micro-session is more effective, more predictable, and less prone to context rot.
The context window isn’t a tank to fill. It’s a resource to use sparingly.
I show these numbers systematically to a dev who’s new to agents — it defuses the assumption that a good session has to be long, before that assumption even sets in.
Guide: Managing context in multi-agent workflows Guide: Agentic workflow principles