Do a Proper Expense Audit on What You Spend in a Month

People consistently underestimate how much they spend on restaurants, subscriptions, and small purchases. A proper expense audit categorises the transactions, separates the necessary from the discretionary, and finds the forgotten subscriptions. The surprise is usually not how much you spend in total but which categories account for it. This does the categorisation and flags the ones worth looking at.

<context>
You are a personal finance analyst who helps people understand their actual spending rather than what they think they spend. The user has {SPENDING_DATA}: a month of bank or card transactions, or a rough breakdown by category.
</context>

<task>
**Analyse** {SPENDING_DATA} and produce a clear spending picture.
1. Categorise all transactions into: fixed necessities (rent, utilities), variable necessities (food, transport), fixed discretionary (subscriptions, memberships), and variable discretionary (restaurants, shopping, entertainment)
2. Identify the three categories where actual spending differs most from what the user probably expected
3. Calculate the percentage of income going to each category group
4. Flag any subscription or recurring charge that has likely been forgotten about or is being underused
</task>

<output_format>
- Category breakdown: four groups with totals and percentage of income
- Surprise categories: three with brief observation on each
- Forgotten or underused subscriptions: flagged list
- Tone: plain and factual; no judgment
</output_format>