If you don't over-crowd, should never have to 'defoliate" -- this term means removing a ton of foliage without discretion. This canopy does not look over-crowded. well-spaced colas across canopy. Should not have to remove many, if any, leaves. Even under the scrog, i don't clear that out. I might remove some just above the pot so it doesn't trap excessive amounts of moisture, but that doesn't require 6-8" of clearance to accomplish that.
While it is sometimes necessary, cutting stuff off the plant is wasting resources, time and effort. I keep tweaking my process to minimize wasted growth. Minimal pruning is the goal.
Removing a leaf from a congested area is fine. avoiding condensation on leaves is a good reason to do such a thing. Otherwise, your goal should be to keep as many leaves as possible, not look for whimsical reasons to remove them. Leaves do more than just absorb light, so even shielded leaves are value-added.
Removing shoots is a matter of familiarity... How deep do you expect your canopy to be? How deep do you typically see decent buds? Depending on expected growth rates, which will differ for every garden, you may want to remove more or less than the next person. Genetic variety impacts this too, so it's as much a guessing game as anything else. I'd rather have 1 lower branch of meh buds than cut off too much and reduce yield.
i prune to 3 growth nodes at top of each cola at flip to flower... then 14-18 days into flower i'll go through and remove weak lower growth, if necessary. If i think it'll get congested or produce larfy buds, i'll remove it. Usually this only entails removing the lowest 1-2 branches due to the lollipop headed into flower. There's more than one way to skin this cat, i'm sure. Be consistent so you can tweak your process. Take some notes, adjust, try something new until it results in the plant you want.
Even at 14 days of flower, you still have nearly 2 weeks of strong vegetative growth remaining, and more if it's a long flower phase plant.
removing lowers doesn't increase yield... it may reduce effort trimming and give you a greater proportion of 'better' nug quality, but don't trick yourself into thinking it increases yield. If you make extracts, edibles or bubble hash etc, you may want some amount of larfy buds.