While you usually want to reinforce an attack at first, additional reinforcements will often arrive to late to be benefitial and are actually a waste (especially if they get caught). Otherwise, you might want to consider building up your army or teching some counters to his army.Ī really non-intuitive time to power Drones is while you're attacking. If you have an army close to your opponent's in size: Power Drones. So the question of "When to power drones" is best answered by knowing the size of your opponents army. Unless you need units you want to be building drones and upping your enconomy. This isn't usually practical, but when discussing when to power drones it is useful. Ideally you'd like to hold off on building units as long as possible and then only produce them right before your opponent reaches your base. So Zerg players often alternate between powering drones and building units. While the other races have to make this choice as well in mineral distribution, Zerg also have to make it in production. Unlike their Terran and Protoss equivilents the Zerg can produce Dones at a much faster rate, the trade off being that they have to choose between economy and army. There are a number of times when you want to power drones: A lot of people will say: "Zerg should always fast expand," and if you take them at their word you might not understand whyearly expansions are so helpful to Zerg.
So I think at the core of your problem is the question of: Why do I expand? and I can understand your frusteration. I've added my comments on the replay at the bottom, but you can also find them on youtube.