I don't think there's any real shortest time frame; just depends on how long you're wanting to hold and how much gains you're wanting to make, different patterns have different time frames and some form quickly while others form longer, like a Flag or Ascending Triangle needs certain amount of times for candles to touch the upper and lower lines but you can sometimes see it forming before but need it to confirm properly first and other indicators go with it, Cup and Handles take longer to form and aren't as common and can't be used to predict until it's actually formed where some patterns can be used before they are fully formed. Just comes to knowing all the different patterns which I'm still learning myself and remembering them as well, they start to stick out at you once you've been doing it for a while though.
I use the daily chart but also use the 10min, 30min, 60min intra day charts as well as that can sometimes indicate a true pattern of a stock especially when it's very volatile and they can present some great entries as well as indicate when time to exit, like if a stock is moving up and hitting new highs, the intra day charts will say if it's exhausted but depends on your trading time-frame/target for holding and profit. A pattern on an intra day chart might not last more than another 10min or 30min or 60min so wouldn't be a hold for a few days, at the same time it can give you an idea of a good entry to not buy at the top and the daily will concur with a different pattern if it's right to go long.
Yes a flag on a daily can be used for an entry timing and a prediction of where the stock will go, but need to know when that flag is going to come to a reversal point before making the entry. KSN for example has been in a Flag pattern which is becoming a Channel, but now starting to reverse and there are individual candles, candle formations, bouncing off support, MACD, EMA, Volume all these signals coming together with the Flag that indicate the reversal is coming.
All dependent on the patterns and formations, flags can be really short but also depends on other indicators and the formation of candles, types of candles, the MACD, EMA, MA lines, Volume. Can sometimes have a flag but those other indicators are not in favor of a reversal. Patterns though are the accumulation of candles, sometimes it's an individual candle such as a dragonfly doji at the end of a downtrend that is a good indicator of a reversal and entry for a successful trade.
Can have really good successful trades on short time frames, sometimes they end up being day trades by accident or the next day or few days. Just a matter for finding the right setup in a stock; either the right pattern or candle/s and being at the right time.
For instance I tipped CXO the other day when it dropped and I bought some at 8.5 and 8.6, it then bounced from that Inverted Hammer the next day up to 9c which I could have taken some decent quick profit before it dropped off again but my targets are a bit higher and there are other patterns in that chart and indicators to suggest and support my prediction of it going higher in the near future.
Hope that helps explain, kind of rambled on there, just my personal thoughts and opinions, I'm still learning everyday as well.
