Or should we say, the top alts have the possibility to exist longer. Because it depends on the foundation itself of the project, whether it will survive or not. As we have seen, a lot of alts already disappeared in this market. Only few are worth investing at. And besides, before you go to other alts, you can always include bitcoin in your portfolio. In this way, you are holding the top currency, which has better chance of surviving as compared to these alts. There is no right time to buy or sell, as it depends on your financial capability. How long can you hold on this market?