VPD is very important, way more than the nutrients, and prolly the hardest to dial in for hobby growers on a budget. The only time mine is really tougher to keep in range is the winter time when the air gets so dry. The other issue managing VPD in hobby grows is the constant air extraction to maintain the best range possible, the plants don't have access to enough CO2 for higher performance growing with constant fresh air moving through, a trick is to find the sweet spot for air extraction that allows the plants some Windows of time to suck up CO2 before the air is replaced and temp/humidity doesn't spike to high---takes timers & controllers & monitors. Another very over looked thing in VPD is its based on leaf surface temps against the air humidity and NOT the room air temp. You will loose sleep trying to keep VPD in check!! Then it takes understanding how these numbers work against the moisture in the plant That the roots push up and out from the soil moisture. So when numbers go to high or low it can literally push back or pull too much and starve or burn the plant. A under watered plant is crushing to the plant,water pressure lost = plant droops & microbes die, ph buffers go whacky, domino effect!! Same for over watered plants = not enough water pressure to move the high volume, roots sufficate, anaerobic microbes take over, ph collapse, domino effect..LOL...A plant will build it metabolism based on the VPD it grows up in, within reason, so as long as we get close as possible we should be fine.....the main goal is to be consistent with day & night time temp/hum fluctuations and the plant will grow acustomed to its surroundings. But if you can hit the proper. VPD marks with high power lights, growing becomes a dream!! I'm no VPD PRO but I think anyone that wants to try and grow the highest quality possible needs to read up on it, and try to hit the best range possible. With this and some basic knowledge of how plants eat(TEAMING W/ microbes & NUTRIENTS) will help growers to better use Nectar, teas, plays well, the BIBLE, etc. This means you all have HOMEWORK CLASS!!....LOL....for real though....