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
Holding bitcoin is obviously good idea to earn money.You just need to wait for the correct time to buy and sell.for example I bought 3btc when bitcoin price was under 400$ and now it's 770$+.So you just need to be patient and wait for the correct time.
you are right that wait for the correct time to buy and sell your bitcoin and i also buying bitcoin with low price and then i wait for higher and when price go to high then i sell it with high price and get a good profit from bitcoin trading .