People says that bitcoin should be hold for lengthy time of at least 4 to 5 years of duration but I think that I you have maximum profit during bear season in less time then you should sell it because market will not always gives you maximum return. The desire of getting more and more will make you looser because there is not a single person who is thankful for the money he owned but instead everyone wants to earn more than this. Patience is the key to success and those who cannot wait for the bull season and make wrong decision cannot get profit. bitcoin is risky but there is no other coin which is more successful than bitcoin but one thing that matters a lot is the accurate decision during unfavorable conditions.