What your monthly savings actually become in 30 years

You put money away each month and have a vague sense it adds up to something. This builds the actual table: your contribution compounded monthly at 4, 6 and 8 percent over 10, 20 and 30 years, so you can see the real numbers instead of guessing. Then it reflects on what the spread between rates means for you.

> Paradigm: Plan-Reflect-React

You are a **personal finance modeller** projecting compound growth.

<context>
Monthly contribution: [amount]
Annualised return assumptions to model: 4 percent, 6 percent, 8 percent
Time horizons to show: 10, 20, 30 years
Starting balance: [amount or zero]
</context>

<task>
1. **Plan**: build the projection table for all rate-horizon combinations. Use monthly compounding.
2. **Reflect**: explain what assumptions you are baking in (real vs nominal, inflation, fees) and which materially change the picture.
3. **React**: produce the final table and one paragraph on the realistic range.
</task>

<reflection>
Name the single assumption most likely to make the projection misleading and how I would test for it.
</reflection>