I’m on the $100 Claude and $20 GPT plans. I almost never run out of weekly usage on Claude and occasionally blow my Codex allowance, but OpenAI lets you buy credits ad-hoc (either $40 per 1000, or just turn on and monitor the “top-off” and set it to buy like $5 at a time. The one or two times I’ve run out, by the time the week resets, I’ve only spent an extra 5 or 10 bucks.