The whole point of having accounts on different crypto exchanges is to a) spread your risk, as most exchanges aren't yet regulated, and b) have access to a broad spread of currencies, as not all coins are listed on all exchanges.
I was delighted the other day when www.binance.com reopened their doors after their New Year rush, and I was able to sign up. I'm a bit short on BTC at the moment, so I then went into my Bittrex account and... wait for it.... transferred the entire remaining BTC balance out of Bittrex and into Binance.
That was great, in that it allowed me to load up on some ZEC.
Later the same day, though, I was looking at the ADA charts on Bittrex, wondering about an entry point, when the full force of my foolish folly struck home. Taking my BTC balance to zero on Bittrex means that I now can't buy anything on Bittrex!! Doh!! So now I need to either liquidate something else on Bittrex, to create some liquid BTC, or move some in from elsewhere, or buy fresh.
It's not a disaster, and certainly fixable. However, just be aware (of the blindingly obvious) - it's not enough to have multiple exchange accounts. You also need to keep them properly funded.
Expect to thrive...