I like to take off what i *know* will be trashy fluff... i err on the side of keeping some. So, if familiar with the zone in your canopy where good buds grow, don't cut into that.. miss by more to be sure.
new lights or first grow? be a bit more conservative. I think i have a good example of lollipopping in week 2 or 3 of my GGxWW diary... should see a canopy and lower view too -- it's a flowering plant, not what the diary is about. don't be surprised it's a vege week, lol.
Now, if you mean just below canopy.. .leave that.. the idea of removing foliage is to improve photosynthesis to more areas of the plant to spread reserouces... Resources are somewhat mobile, but less efficient growth will result in the areas with very little light hitting leaves. it will be depending on it being trucked in from elswhere in the plant... not optimal / low priority.
prune anything below teh sweet zone too.. rip off new auxiliary buds about to grow anywhere low on plant... it also improves visibilty when giving a looksy for nanners later too.
i do this when it has 7-10 days left to grow back a bit... the leaves you remove will somewhat be replace, but a bit smaller and by that time the growth should have mostly occured in the other areas to some extent. plus, less blocking going forward still.