I kinda like Gann's HiLo Activator. I just put it on the chart today. It might not last the week, but looks interesting.
However you choose to define a trend, when it starts and when it ends are randomly distributed through time. Thus the best model of market movement, even with all of it's shortcomings, is still random walk. Even random walks produce patterns that look like trends in hindsight.
In that case, why not 21 or 55? I am not giving you a hard time, just want to learn something new. Thanks.
This IS the "mother of all questions", we all will never know for sure. My favorite market wizard is, of course, Tom Basso, very generous in sharing infos. He told me & other fans that Keltner channels are his favorite tool to determine a trend, but I'm sure he uses other tools as well. I hope he'll participate someday on this forum, too - he managed 600 million US$ peak assets at his firm Trendstat capital before retiring in 2003. This is his "like" page on Facebook, https://www.facebook.com/enjoytheride.world/
How to Tell when a Trend has ended? Looks like Rayner has been putting some thought behind this too... “Hey Rayner, how do I identify the direction of the trend?” " it’s not as simple as it seems — even if you use trend indicators. For example: The Daily chart is in an uptrend. But when you go down to the hourly chart, it’s a downtrend. And if you go down to the 5-minute chart, it’s chopping all over the place." his conclusion is interesting. https://www.tradingwithrayner.com/best-trend-indicators/ Search: How to Tell when a Trend has ended? https://yippy.com/search?query=How+to+Tell+when+a+Trend+has+ended?
George Soros — 'It's not whether you're right or wrong, but how much money you make when you're right and how much you lose when you're wrong.'