Take it from someone that learned hard lessons in 2017. Alt coins are for short term rides, don't get greedy on trying to make a huge profit off of them. Make you lil profit, then move it to bitcoin/Ethereum.
That's entirely dependent on the alts you hold. In a bullish market you do not want to exit your position early. You could sell at 5x and miss a 20x while you moved to BTC or ETH and they go sideways.
When alts run BTC doesn't. Just ride the wave.