That actually depends on the market, because there is still a chance that value will go down in the future but for now with the current value of bitcoin - i think it is better to hold it for a long a time.
Yeah holding for long time is better for maximum profit. But not holding so long like many years, try to spend your bitcion time by time, because bitcoin is made to make its users life happy, so your life become happy when you fulfill your desires so try to fulfill your desires by bitcoin, do not spend all of your bitcoin try to save it for future.
It is quite better to make holding to your bitcoin. Holding a bitcoin for a long time is. Yes, so yielding in terms of profit.
Do not hold for so many years I suppose but it may be 2 3 years enough. After you just sell the bitcoins and you will be amazed to see the earnings you will from it.