Stock trading has to be done only if have time every day atleast for an hour. Technical analysis help to find out the trend and invest. Dow Theory prescribes to follow the trend and never go against the trend. Dow theory is not forecasting, therefore it is not possible to know highest price to sell or lowest price to buy. Only when trend is know along with volumes, then buy or sell can be made. Dow theory is old and even now it is followed. It is useful to find the trend.
My understanding is technical analysis is very useful in trading. We can reduce the risk. We can follow certain theories and follow strictly, we can make profit from the stock market.