I think holding long term will help cut your losses. Coins will drop down -50% or so sometimes, but eventually bounce back up. Key is to hold them for longer than a year or more. Eventually they'll get you into profit. That's when you sell. But, you can't buy into coins that aren't worth anything and expect to do well. You can't polish a turd into gold.
This is right, but if we're talking about the amount dedicated for trading - allowing it to be stuck in positions for long term isn't always an option as you may end up with no free BTC to trade with.