I use them for one thing and one thing only. To preserve muscle when dieting. When i am maintaining or bulking up i have no need for BCAA supplements, with all the protein i get in it would be a drop in an ocean.
When dieting, IMO they are a very effective way to offset catabolism without the calories a protein shake or turkey breast would yield.
They are great for during a workout and before, they are great to use in-between meals and they are great to use when you go pee-pee in the middle of the night.
I'd use 3-5g a time only.
Added to a controlled carb or keto diet with high protein and moderate fat intake and you will preserve more muscle with them than without. I don't waste my money otherwise.
Being on or off cycle is really of little importance. While of course AAS make a vast difference to the gains you keep when dieting or make when not - they will not substitue or make up for any discrepancies in diet - especially when cutting.
I use the term cutting with a definite meaning in mind - to mean the lowering of fat to levels well into single digits - ie. <8%. Anything more than this is not 'cutting' IMO and is just 'a bit of fat loss'!