How many open trades is too many?

What if having multiple positions open in parallel could help or hurt your trading?  

Below, we can see the edge of Steve, a trader who generally underperforms when only having one position open. If he doesn't have a trade on, Steve feels that he's missing out. So he breaks his rules, and enters a trade without any plan. These FOMO trades cost Steve money:

Now let's turn to another trader, Ted, who employs a good swing trading strategy, but will frequently get bored of waiting for his swing trade to mature, and will go open other positions just so he can be actively trading while passing time. He doesn't believe it amounts to much, but if we look at his edge, it tells a different story:  

His single product swing trades do him quite well on average, but it's this bored 'trading for the sake of trading' that's losing him money.

Which one of these are you? Make sure you only trade your plan and remember NOT trading is often the best plan.