Bitcoin keep on falling down and no sign of raising. How long can we keep holding?
Till you can get profit, you will not loss your money if you don't sell your coin in lower price. A few years ago bitcoin price is only about $200 but in line of bitcoin adoption the price is now increase, just wait.
That is right. There is no constant or one standard time frame where you can wait for before selling your coins, especiallty when the market together with its assets are all but falling down. It is not too smart to do business when you would end up losing like that. So, the time you would to wait is until you get some semblance of a return to your investment.