Home / Never running out of tokens
The right habits for saving
Several short sessions attached to a project make Claude reread far less material than a single session dragged out from one day to the next.
A Claude session dragged out from day to day reloads, with every new question, everything already exchanged before it, as the lesson on the token and the context window showed. The older a session grows without being closed, the more quota each new question consumes, even a short one.
Why a marathon session costs more than it looks
The mechanism comes down to how the history is reread. Every element already written in a session, message, answer, file, stays present and gets reread with every new exchange inside that same session. Extending a session from one day to the next, rather than opening a new one, therefore means having a little more material reread each day than the day before, with nothing ever removed.
The project, a container that avoids losing everything again
Closing an old session does not mean losing the thread of the work. A project brings together in one place reference files and an instruction written once and for all, and any session opened inside it finds them again, the next module of this course comes back to this in detail. What a project does not do needs to be said clearly: it does not summarise your old conversations on its own. A new session attached to the project starts light because it does not reload the history, not because the project has condensed it for you. The project still brings a measurable gain elsewhere: Anthropic's documentation states that documents attached to it are cached, and that only new or non cached portions are counted, whereas reattaching them at every session would charge for them every time. What needs to carry over from one session to the next carries over because you wrote it in a file or in the instruction, or because you ask for it again.
What this changes in practice
Session unique, prolongée sur trois jours :
jour 1 : messages 1 à 20
jour 2 : messages 1 à 20 rechargée, plus messages 21 à 45
jour 3 : messages 1 à 45 rechargée, plus messages 46 à 60
Trois sessions courtes rattachées au même projet :
jour 1 : messages 1 à 20
jour 2 : nouvelle session, elle relit les fichiers du projet, puis messages 1 à 22
jour 3 : nouvelle session, elle relit les fichiers du projet, puis messages 1 à 18In the first case, the volume reread grows every day without ever going back down. In the second, each session starts from a short base.
The habit to adopt
Faced with an already long session and a task unrelated to what has just been dealt with, it is better to close it and open a new one attached to the same project rather than have it pick up the thread. This choice loses nothing of what is written in the project, and it avoids rereading every day what was already dealt with the day before.
Marathon session against short sessions attached to the same project
Every day reloads the entirety of previous days before adding the new exchanges.
Each new session starts from a short base, with the essential points found again via the project.
A person keeps the same Claude session open from Monday to Friday during a first week, dealing with a different task each day from the one before. The following week, she closes her session every evening and opens a new one the next morning, attached to the same project.
Write in one sentence what this situation establishes, and in one sentence what it does not establish.
What this establishes: This comparison establishes that the first week has a history reread that grows every day, while the second starts from a short base at every session.
What this does not establish: It does not establish the exact amount saved over the week, which depends on the precise volume exchanged during each of the two weeks.
The three most common miscalibrations
- Too broad Closing your session every evening entirely removes the token cost of your week's work.
- Too narrow This comparison says nothing, since it concerns a single person and only two weeks, not the whole cooperative.
- Beside the point It establishes that the tasks dealt with in the second week were easier than those of the first.
- Every element already written in a session gets reread with every new exchange in that same session, without ever being removed as long as the session stays open.
- Extending a session from one day to the next grows the volume reread each day, even when the new question asked is short.
- A project keeps files and an instruction that every session finds again, it does not summarise past conversations on its own.
- Closing an old session loses nothing of what is written in the project, only the thread of a conversation that is no longer needed.
Find the oldest Claude session you have left open, count the days since its first message, and close it if its subject is finished. Whatever you would want to keep from it, write it down somewhere before closing it.
Every datable claim in this lesson links here to the public text behind it. A source that does not open proves nothing.
- Anthropic, best practices on usage limits consultée le 2026-09-02