I don't hold my bitcoins for a long time. Having studied the trends of bitcoin for the past 6 months, I feel it is better to hold your bitcoins when the prices are low. This should come after a heavy slump-down in the price. Once the prices start rising, I monitor and sell when there is a difference of more than 50% in price change. After selling, I wait for another period when there will be a significant drop in the prices again. I don't want to make a mistake of holding the bitcoin and then the price falls permanently leading to loses.
You don't get such chances very often and the highest change in prices per monthly basis would be around 20%(approx..) and it would be risky to hold at such rates.However,the price might not fall permanently and if it does then it wouldn't matter how much you hold cause it would be the collapse.it on installment basis and make good profits out of it.
I think holding it is risky in itself and dumping in installments increases the volatility IMO.But that is quite risky because the value is not that low. And I hope that more people will sell it later with some profit.
. 