Postel's Law
Be flexible in what you accept from people, and careful and clear in what you give back.
Why it matters
People enter things in many ways. Rejecting reasonable input creates needless errors.
How to use it
- Accept phone numbers with or without spaces.
- Handle pasted text gracefully.
- Return clean and consistent results.
Example
A date field that accepts "12 Nov", "12/11" and "tomorrow" causes fewer errors than one strict format.