Altcoins are not reliable for the long term, the successful tactics with alts is buying when no one is buying and selling when you are in profit, it is not something you cab hold for a long period of time.
It's not all coins that you should buy when others are not buying. Some of the altcoins on the market now might be in their vanishing stages.
When I refer to vanishing, I mean that the project may lack the ability to compete with others, and the project owner may have already depleted their liquidity. If you fall victim to buying such a coin, you might end up holding it forever, as the chance of selling it at a high price to make a profit might not come.