Legal
Terms of service
The agreement
Who the contract is between and when it starts.
Your account
Eligibility, accuracy of details, responsibility for activity on the account.
Acceptable use
What the service may not be used for, and grounds for suspension.
Your content
You keep ownership of your trips and expenses. Set out the licence needed to operate the service, and what happens to shared trips when one member leaves.
Paid plans
Cross-reference the subscription terms for billing, renewal, and cancellation.
The calculations
Important for this product specifically: SplitEasy computes suggested balances and settlements. State plainly that it is a record-keeping tool, not financial advice, and that it does not move money between people.
Liability and termination
Limitations, warranty disclaimers, how either side ends the agreement.
Governing law
Jurisdiction and dispute resolution.