my thoughts are likely to differ from others..however i can draw the greatest trendlines that fit really well in the past, but as a means of defining where the trend line should be now...
(should it be on that high, or what about the close for that bar as it "fits" better, or what about that high which goes past that line)...i think it fails miserably.
I would rather use an indicator to tell me what the trend is, than a trend line
i may get in slightly later, i may get out slightly later..at least i know precisely when, with my own criteria which is more important to me.