For most traditional investments like stocks and bonds, one of the key tenets for a successful outcome over time is to “buy and hold.”
Of course, you are well-served to start with a low-cost mix that is diversified globally, having exposure to different sizes, styles, and sectors of the market, and suitable for your personal circumstances and situation. Along the way, you should make adjustments when you experience life changes, and rebalance as market movements shift your mix out of alignment from its original setting.