Everyone is a genius in a bull market. When stocks are going up the best approach is to own them. It doesn't matter what your time frame or style might be. If you own stocks in a bull market you should do well.
Markets tend to be in a bull phase much more often than anything else so the issue of investing and trading style is not always considered that carefully. Who cares what you call yourself if you are making money? It is in bear markets and trading ranges when style becomes much more important. Stylistic choices in bear markets make a tremendous difference in returns.
A good example is seen in hedge funds. Hedge funds have a tendency to underperform in bull markets because they don't stay fully invested for the entire trend. They tend to produce substantial outperformance in poor markets when market timing and stock selection becomes much more important.
Longer-term investors tend to dismiss the idea that markets can be timed to any great degree. They believe that if they hold good stocks for the very long term they will enjoy Buffett-sized returns over the course of decades. That certainly does work but the downside is that if they do stay heavily long through thick and thin then the opportunities to take advantage of lower prices in the inevitable bear markets are diminished.
My tendency is to call myself an opportunist rather than a trader or investor. I don't want to decide upfront what time frame might be the best. I simply want to hold my stocks for as long as I believe it is productive to do so. When you become beholden to the title of investor or trader that limits your choices.
Warren Buffett is a good illustration of how these titles can mislead. Buffett is considered to be the ultimate long term investor but he is also a very aggressive trader. He takes advantage of opportunities when they arise like in 2008-9 when he cut some great deals in the depths of the despair. A long-term investor wouldn't tend to do the deals he does but an opportunist would. Purity of style is not important to Buffett although those that embrace a long term buy and hold approach would never admit it.
Recently many long term investors have made some good buys near the market lows. The question they have to be pondering now is whether they want to stick with long term convictions or do they want to be more opportunistic and take advantage of profits that materialized much faster than they anticipated. Do you stay loyal to your style or do you change your approach?
If you view yourself as an opportunist the question is not so difficult. You take advantage of good fortune when you can and they look for the next chance to do it again.
There often seems to be some psychological need for some investors to stay loyal to their stocks. They become emotional invested in the process of owning something and they tend to forget that the goal is to maximize returns.
There is always a place for holding certain stocks for the very long term. I've held certain names like Altria Group (MO) , Abbott Labs (ABT) and Johnson & Johnson (JNJ) for nearly 30 years but that is just part of my approach. Ultimately it is the opportunistic mindset that drives what I do and that creates the best returns.
In a bull market, style doesn't matter that much but in a bear market, it makes a huge difference. Don't pigeon hole yourself into a certain pattern of action when you see opportunities. Be clear about what you are trying to do and don't be too hung up on time frames when the market is volatile and moving quickly.