I have some investments in Ethereum and Litecoin. I always like keeping most of my investments for long term because projects need time to show progress. Holding good coins and cryptocurrencies with strong project is always good and can give good returns but holding useless coins is not advisable. You need to analyse all coins before deciding to hold them. You should always do complete analysis and research before investing in any coin. If you would have invested in bitcoin or ethereum in beginning, and if you would still hold them, then you would have got tremendous returns. So if invest in strong coin and hold them for a good time, you may get good returns. Analysis of project involves reading whitepaper and researching about the project.