there are about as many different opinions on defoliation as there are people growing herb. This is what I do and it works for me. Through veg and early flower, up until stretch finishes, I pinch all lower shoots and force all of the growth out to the tips of the branches I am going to flower. I leave the leaves though to power the plant through the stretch. Once stretch is over, I defoliate liberally. They may be solar panels, but if they’re not getting light anymore, they are creating humidity, obstructing airflow and leaching moisture and nutrients for almost no return. I grow in coco so I don’t really need a store of mobile nutrients for late flower. I control that with my feeds and taper them off when the plants are finishing. This is by no means the “right“ way to do it. I have grown them totally native and I have also stripped off every fan leaf that was older than two weeks throughout their lifecycle. All has its pros and cons. Play around with it and see what works best for you, your space and the strain(s) you are growing. You are not going to hurt the plant or destroy your yield or anything like that. Good luck. Cheers