That said there are several other aspects that need examination before deciding when and where to invest.
Efficient Market Hypothesis postulates that "only fundamental factors, such as profits or dividends ought to affect share prices" (Stock Market). But this is true only in an ideal situation - a perfect market - which is hardly the case. Over shorter periods, there are wide variations in stock prices on account of any number of reasons, some of which are not even technical in nature. The stock market is driven by investor confidence - and that is a matter of personal choice that cannot be predicated. The general mass of investors invests with a 'herd mentality'. Inexperienced players can rarely, if ever, 'time the market' and hence generally incur losses. Warren Buffet has said in his biography that, "...despite all this available information, [analysis, 'hot' tips, blogs etc], investors find it increasingly difficult to profit." He continues, "...Sometimes there appears to be no rhyme or reason to the market, only folly". The market crash of 1987, resulting in a 22.6 percent drop in the Dow Jones Index, could not be traced to any specific cause, and is just one example of this 'folly'.
Since timing appears to be the critical factor, it follows that one's holdings have to be monitored continuously.