Pick a mix of US stocks, international stocks and bonds, choose a stretch of years, and see roughly what it would grow into at long-run average returns. Then try rebalancing, or adding a little every month, and see what actually changes.
Returns are simulated from long-run historical averages and assume smooth compounding. Real markets are volatile and past performance does not guarantee anything. Estimates for learning, not investment advice. FinMango is a 501(c)(3) nonprofit.