Indeed, holding Bitcoin for significant period of time and consistently adding more Bitcoins in your portfolio by employing Dollar cost averaging strategy (DCA) is a prudent approach. The historical performance of Bitcoin has vindicated that it has potential of substantial growth and ability to outperform other class- of assets, including gold and stocks, in the long term. However, decision to continue holding and acquiring new Bitcoins entirely depends on individual's financial situation and circumstances, additionally  there is always risk associated with all type of investments including Bitcoin, therefore it is wise to carefully evaluate your financial situation, long term goals and risk tolerance before making any investment decision.