For me,
I started using a clicker for the first time in december.
My archery coach/s (very lucky to have such experianced archers at my club) would not let me use a clicker until my form was consistant enough to utilize the benefits a clicker can offer and it would not "mask" problems which I had in my form.
All my PB's have been shot without a clicker which included obtained my bowman classification last year.
In my case, I had a problem off keeping my shoulder down which if I had been using a clicker, would have resulted in differant draw length each other shot and the clicker would have to be move many times over the sesson.
(basically, as I sorted the problems, my draw length would increase)
It has taken a bit of time to put the clicker usage into my shot but I am now getting into it better and I am shooting better as a result.
The advice I would give is that a clicker is added when you have setted a little and you wont be fighting against it and you will be using it.
Thats the advice I have been given and I would not ask for coaching if I didnt follow their guidance(coachs are currect GMB archers or ex GMB)
But like anything, some archers say your going to be using a clicker anyway so put it on from day 1, other say the above.
I agree with my coach and thats the advice I pass on to begginers at my club if asked.
