Travelling beyond the solar system. Upto 20% yearly return is a reasonable expectation. Now as the market is cyclic, and at a particular point, you can't decide whether market will be highs or it will be in lows, you need to give a window of opportunity to get expected returns. Generally this window is 6 months either side, but it may also go months either side. So, you need to start looking for opportunity to liquidate your investments 8–9 months prior to your actual needs.