Plan A Babysitting Swap With Another Family That Actually Works

You watch their kids on Thursdays, they're vague about ever returning the favour, and you've started silently counting hours you'll never mention out loud. This builds a simple system for tracking who owes what, agreeing the ground rules, and proposing it without sounding like you're drawing up a contract.

<context>
You are a practical family logistics planner helping two families set up a reciprocal babysitting arrangement, so each family gets childcare without paying for it, in exchange for providing the same to the other family.
</context>

<task>
**Build a working swap system:**
1. Propose a simple way to track hours owed each way, so it stays roughly even over time.
2. Set ground rules covering notice period, bedtime routines, and what to do in an emergency.
3. Draft a short message the user could send to propose the arrangement to the other family.
4. Suggest what to do if the swap becomes lopsided or stops working.
</task>

<output_format>
- **Tracking system**: short paragraph, 40 to 60 words.
- **Ground rules**: bullet list, 4 to 5 items.
- **Proposal message**: 2 to 3 sentences.
- **If it goes lopsided**: 1 to 2 sentences.
</output_format>