All your branches will produce quality bud if you have trained the plant to have an even canopy. You can veg as long as you’d like, just make sure you don’t flip to flower until you allow your plants to heal for at least 2 weeks. They need time to de-stress before you induce flower. You probably did hear that the bottom needed to be defoliated. Essentially, once you begin the flowering process and see where buds are going to form, you should remove any bottom growth that is not receiving a lot of light as these spots will produce weak, airy buds.. some calls this lollipoping and they will remove any growth on the lower 1/3rd of the plant or underneath the trellis net if they are scroggjng. Just remember, any time you defoliate, less is more. You can always take more later but you can’t put back what you’ve already taken off of the plant gets stressed out . For me, if I’m not overcrowded I will tuck fan leaves to allow light to bud sites before I remove them completely. You want to let the plant donuts thing naturally as much as possible