Most people cite it takes at least a hundred dives to dial in your buoyancy. I disagree and my students have it dialed in before they leave the pool. There's a guy here this week that's been a diver for 7 years and he's still not happy with his buoyancy. I talked him through a few strategies last night at dinner and he was amazed at how easy and effective they were. I've never had a student whine after the class about not being allowed to kneel. I've never heard anyone complain that a diver was ever too horizontal or neutral either. By many accounts, it's the hardest to achieve, so I introduce it right after I teach mask clearing in the Kiddie Pool. Every skill is built on the base of being neutral, and every description of every skill begins with "Establish neutral buoyancy". I try to avoid talking on the surface and instead prefer to demonstrate below, but I do bring it up on any debrief. By the time we work to the final test in the pool, they've got neutral buoyancy down. BTW, when a student is in control and relaxed, I find that they learn skills at an incredible rate. When they're fighting the awkwardness of kneeling on the bottom, they are often distracted by that and learning takes longer.