I think holding a bitcoin for a long time is a good thing cause the value of bitcoin keeps on getting high just think about this when bitcoin made its first appearance the worth of 1Bitcoin is 0.08$ look how much its price grow from its appearanve
to me i think it depending on the interest of the people, as some people are always interested in long term investment, while other people do not good in long term investment as by nature they cannot wait for such a long time and they always give preference to short time investment.
basically this depends upon at what price you acquired your coins.If you are a miner you should cover all the expenses and must have a good return for the time you spend and it is wise to book your profits as you go rather than keeping for a very long time.