Never had any therapy in my life. Critical debriefs were similar I suppose in the Army, when we saw some horrors, but I never paid much attention really.
Overall, a few points to consider.
Freud conducted the first ever free association in his psycho-analysis. He has since been ridiculed by any decent psychologists.
Psychiatrists (the medical wing of psychology) nowadays rarely uses this. Apart from drugs they tend to favour cognitive therapy away from psycho-analysis.
The Church of Scietology (or dianectics), although vehemently deny it, they use free association in their initial sign ups. They call it "auditing" which is pretty much the same thing. Remember, this is a "church" that believes we come from alien lizards. I rest my case on them!!!
And finally Dr Raj Persaud (the "celebrity" psychiatrist) is very much against it. He seems to know what he is talking about.
Like many things in life, I suppose give it a try if you think it will help, but apart from so called dopctors and therapists making millions, the evidence suggests it is not much use.
My view, if you have to dig up the past to path the future, you already know the answers. Unless under deep hypnosis, which I think it quite scary, you already know the answers. why pay somebody to tell them???