Claude's limits are token meters on two clocks, and your open session is what drains them

The billing mechanism is unglamorous, and it is the whole story. Claude Code sends the full conversation with every request, and each time Claude uses a tool it fires another request carrying that batch of tool results, which the dev.to write-up attributes to Anthropic's own cost documentation ^[4]. The price of a message is set by what is stacked behind it, not by what you typed.

The post's worked example is worth keeping. Developer A opens a fresh session and asks 40 short questions about one small file. Developer B keeps a single session open from 9am across three unrelated tasks and sends 12 messages ^[5]. B burns more of the plan, because that one-line question at 4pm draws usage for every file read and every tool result sitting behind it ^[6][7].

Prompt caching is what normally keeps a long session survivable, since re-read history bills at the cached rate rather than the full one ^[8]. On a subscription that cache lives one hour ^[9]. The session window runs five ^[1], so a single window spans five cache lifetimes ^[15], and the first message after a long lunch reprocesses the entire context at full price ^[9].

Two defaults sit underneath all of it. Extended thinking is on by default, thinking tokens bill as output tokens, and the default budget can run to tens of thousands of tokens per request depending on the model ^[10]. Agent teams, when switched on, use roughly seven times the tokens of a normal session ^[19], which leaves about 14% of the run you would otherwise get from the same window ^[20].

Put that beside the price list. Pro is 20USD a month billed monthly, Max starts at 100USD, and both get the same model access ^[11]; Max is sold as 5 or 20 times Pro's usage ^[13]. Entry Max is therefore exactly five times the monthly Pro price for an advertised five times the usage ^[16]. Money buys headroom at par and buys no efficiency, and agent teams alone would swallow the upgrade. Clearing context buys the same headroom for nothing.

The weekly meter is the one that ends the week. It resets at a fixed hour assigned to the account, and you can stay inside every 5-hour window and still be finished on a Thursday ^[2]. The housekeeping that rescues an afternoon compounds over seven days.

One diagnostic decides whether housekeeping helps at all. A session or weekly limit message is plan-wide, and /model will not rescue you; an Opus or Sonnet limit is model-specific, and switching family genuinely keeps you working ^[14].