Reliable method to know when a "trend" has started?

Changes in the trend can be calculated using technical analysis. for example, if the trend of sharp teeth at the bullish trend it will soon diminish, and vice versa, if the sloping steps, it is likely to continue the trend. You can not just forget that every jump is pursued relaxation.

Nothing is sure, especially indicators. They usually lag and will 'tell' you about the new trend long after it started already. But many technical traders are familiar with the candlestick patterns and signals and they use them successfully.
What I do is trying to spot the new formed lower highs and higher lows. Check the pic I found on good old Google below.

This doesn't always work because some currencies move much more chaotic than others, but in many cases it will tell you when the trend started to change. You should also be aware of some candlestick reversal patterns, like ones below.

But that's not enough, either. You should also pay attention to the S/R lines, for example. And you could use the candlestick signals to spot the right entry.

Those are bearish signals, reverse for the bullish ones.
I hope it helps.
Cheers.

After reading and going thru all the previous posts and now I finally understand why so many traders failed in their quest to be an profitable trader. There is no way that they gonna make it if they are struggling to know something as basic as this. Some knows what they dont know and wish to know(like the OP) and most dont even know what they dont know!! Amazing....

Knowing when a trend ends/begins is only just the basic..next you have to know whether the next trend is going to be a ranging or another trending trend then you have to know when and where you need to enter where to place your SL when and where to exit or take profit. Even having know all these they are still risks like events risks, CB interventions geopolitical issues that we need to contend with. That is the reasons why so many have failed and failed and still failing.

I can actually tell you a very simple indicator to answer what you wish to know but I am afraid its not going to be much help unless you learn and know the rests which I have mentioned earlier. Even then the risks is still there as in the recent case of SNB saga whose magnitude is unprecedented and had even sealed the fates of some prominent brokers and market makers. The odds is stacked against the retail traders and even more so now with the advent of HFT and some new parameters. This is the reason why I am now more focused with intraday trades with hard SL and lower my RR to 1:5 using only intraday technical settings based on guerillas hit and run strategy to counter this new era of uncertainty. The downside is having to spend more times eyeballing the monitor and chart constantly.

God bless and good luck on your journey.....

GS.

Trends are how you see them IMO ...... "they" say the trend is your freind , but no-one says "GREED " is your worst enemy...... just as 3 higher lows or 3 lower highs give you and "trend" entry so a "lower low" after 3 higher lows tells u "trend " is over and vice versa ...this came off the web ..I forget who ...BUT it does give you new slant on what a trend is ????

what can be more reliable than looking at higher time frames.imagine seeing a double top on a monthly chart.will you start second guessing yourself?

There will never be a reliable method to know when a trend starts because there is no consensus on what defines a trend. Different people can look at the same 'trend' and point to different places where they think it started and finished, some may not even see a trend.

The common charts that are cited to be objective 'trends' are such only because all the fractal dimensions of the market were trending at the same time, thus appearing as a 'trend' to the most people.

Hmmmmmmm

Does a trend begin with a reversal or a breakout?

Reversal precedes breakout.
No breakout, no trend.
Have to connect the dots.

A trend only exists in relation to your stake in it.

and, by extension, the market is real when - and only when - you have a stake in it.
Everything else is pure fantasy and delusion

Go to the daily chart and look for S/R or MACD simetry to identify cycles.

Then go to the 1 Hour chart , and wait until price starts moving sideways and enter on the direction of the daily (downtrend on the example) , and go short