Nothing stays the same in this life - the same goes for altcoins.
For any given government, organisation, or individual to succeed, accurate knowledge, action taken based on that intelligence gathered as well as the ability to swiftly react based on the changing circumstances are essential.
Altcoins with backbone, that are supported by proven entities, with a professional team of pioneering people behind them and a clear vision are worth investing in.
Go through each altcoin team's actions, their work, their ethics as well as results. Deeply study what it is they have done, what it is they are doing now and what they've got planned for the future.
These are the organisations that in the long run will last and their tokens are a sound investment no matter what the trent is at any given point within the crypto-currency world.
The only problem with this is not a lot of the developers and their team have open histories. A lot of them are newbies in the scene and have arrived by creating a coin and trying to offload it to the public.