holding bitcoin a long time is good but you need more money to invest for long term invesment so you can get x2 or x3 of your money the more you invest the more money you will get.
It is probably the best investment around these days to buy and hold as much Bitcoin as one can afford to, nevertheless caution should not be thrown to the wind, as the technology behind this invention is not set yet and couple of changes likely to jolt its market value are still ahead. From time to time especially for an average investor, take profit and possibily diversify your investment using your profits and be on the lookout to buy back some Bitcoin when price drops.