I have read dozens of threads saying you need to keep your BTC on a hardware wallet or paper. Anything online isn't safe they say. When trading that is not really feasible is it? I like to move in and out of positions several times a day and often at a moments notice. My trading account has a sizable balance (to me - 5 figures) in it.
How risky is this and any additional things I could do?
For those advising to keep funds out of exchange sites, knows what they are saying and the issue of BTC-e comes to mind where the amount you can get for now is 55% of your fund for someone having the amount you have there, its definitely loss of sizeable amount of investment which the balance might not be available again and even if it does, not at the right time. For me, the past is a fundamental lesson that should shape our decision not to fall in the same situation those that have gone before us have witnessed. Just keep it where you can control it.