I do believe we are headed to a downward trend, but people will have plenty of time to sell... I am constantly buying/selling with each swing, making 2-5% each time... This won't be a fast crash down so take your time if you decide to sell 
smart man.
I fully agree, am doing the same. Buy and hold would have earned me around 500% with bitcoin this year, I am around 1000% by simply selling as it goes up and buying as it goes down.
What signals do you use to decide when a trend is about to change?
I am not using signals. I have a fixed allocation to bitcoins, say 20% of my portfolio, if bitcoins go up this 20% becomes say 25% of my portfolio and I sell 5% so it's back to 20%, and when it goes down it drops to say 18% of my portfolio, I buy btc as to bring it back up to 20% of my portfolio.
I explain more about my strategy in this thread:
https://bitcointalk.org/index.php?topic=186617.msg1933492#msg1933492