Im investing a part into poloniex, at lending service, and sometimes into some altcoins a small ammounts, the other part im paying to get my projects live soon as possible.
Saving a lot of money in a exchange like Poloniex could be quite dangerous. It is better to save in your own wallet.
Yeah , never store your bitcoin where you can't access your private key . It's quite dangerous if sometione the sites is scam and closed soon.
That's just preventive way to avoid the unnecessary accident would be happened in the future.
Split your earning to different wallet , it's more safer than place into one place. For me , i use my bitcoin for trading and withdraw it to my bank for my daily life in real life. I don't often play gambling with my money , but i play it with faucet instead because i don't want to risk my money.