If you really want to save on tokens you can experiment with adding more context to the prompt.
My personal favorite is:
Short & direct, [question]
OpenAI give this as context on their pricing pages about limiting or lowering costs:
You can limit costs by reducing prompt length or maximum response length, limiting usage of
best_of/n, adding appropriate stop sequences, or using engines with lower per-token costs.
Pricing page.
There is a setting called Custom instructions It will be a general setting within your chat.openai.com interface where you give instructions how polite or how you want chatGPT to acted. (It’s now only possible for Plus User in a beta state, will be for all users in the future).
More information about this: Custom instructions for ChatGPT | OpenAI Help Center