A few comments I found online...
Take from it what you will
I don’t know how to say this…. But fuck fan leaves. I’ve found you can grow bigger, denser buds throughout the plant with removing them, heavily, multiple times throughout the grow. It helps airflow get through, reduces chance of mold and the plants are happy as fuck.
I suppose if you have 3000 plants though, then fuck fucking the fan leaves, but for a 4x4 it pays dividends.
I agree with this. I remove any large fan leaf that prevents light from reaching lower buds, especially when heavily in flower, and it helps with preventing mould. Science indicates that it’s mostly only nitrogen that is mobile between these leaves and the rest of the plant. That’s why they go yellow.
I agree, I defoliate fan leaves heavily after the final stretch and throughout the flower cycle. Super beneficial in veg to leave them but in flower I have seen no benefit in leaving them in my own personal experience. Everyone’s style or grow tek varies though as well as growing conditions so what works for me may not work for someone else.