Before I sell my coins I'd do some research look for potentials if the coins are worth holding for. Technically,that's the right thing to do wait for the price to be more than the ico price before selling. And buys back when the price is on its dip price when its has a possibility to moon in the future..
Honestly, for me holding coins for months are okay but if you needed the money for some reason you sell, but if that money is kust an extra money then HODL it for as long as you want.
I will try to get more and patiently wait actually i am also doing some other jobs so i don't spend coins in need of money, we should think again and again while cutting out our coins, so before making selling and buying we should check the market that what the condition is and we have to set our target that how much we should buy and how much we will have to wait after buying, so seek best time to buy and best time to sell will be when you will get enough profit of your fixed target and never sell before reaching your targeted price.