first I must say that I've loved this site from afar for a while now (my Droid Stackexchange app) and appreciate all the time you guys put in. That said, I want to ask a simple question with simple answer and try to avoid all of the 'What you really want to ask' stuff that goes on here.

Let's assume I'm playing Terran and I now have the economy to start an upgrade in my Engineering Bay. Let's also assume I'm going for a (standard?) MMM ball, 50% marines 30% marauders and 20% medivacs. What would make me choose to upgrade Infantry Weapons over Infantry Armor, or vice versa?

I'm also interested in when to take what armory upgrades, but if someone answers the Engineering Bay question alone I will happily move the rest to another question.

2 Answers 2


What upgrade:

I would suggest another way: if you plan MMM play - build in parallel 2 Engineering Bays, once both upgrades are started - build armory. You need both of these upgrades picked up to level 3 ASAP.

If you build only 1 EB and due to any reason didn't build another yet...

In game against Zerg: I would upgrade attack in 1st turn. The biggest danger for marines (and marauders probably too) are bannelings. Armor upgrade doesn't help against them.

In game against Protoss: if they have DT/Colossus/templars - armor upgrade doesn't help too - so do attack first. If they have zealot/stalkers/sentries - armor as important as attack. But still I would start from attack upgrade as marines under stim pack are very good for kiting.

In game against Terran: if you opponent play mech: tanks, Thors... armor doesn't help too. so again - start from attack upgrade. If they play MMM - armor and attack same in importance.

Here you could make a decision: don't upgrade armor at all. That would be wrong. Also in game versus Zerg: you are fighting not with bannelings only. You also need to survive some zerling waves, so don't neglect armor updages.

So for general game, I would make following summary:

  1. Start with attack upgrade and follow with armor;
  2. Try to do both upgrades in parallel.

When upgrade

Answer is simple and hard: ASAP (if you play MMM, as you mentioned) or never (if you play Mech).

In game against Zerg: usually, around 8-9 minutes Zerg build mutas. For sure, you need to scout that. Too often you don't have any chance to build engineer bay till this time. But around that time, once spire is scouted - build 2 EB right immediately and build 2 turrets in each mineral line... and start both upgrades.

As I replied to comment, it is worth to build 2 EB, save some gas in order to get both upgrades, but if (due to some reasons) planning to do 1 upgrade only and you detected mutas (and/or mass mutas) it could be worth to start with defense upgrade. Having +1 defense upgrade reduce mutas damage from 13 (9+3+1) to 10 (8+2+0) => +23.1%, but having +1 attack upgrade increase your rines attack from 5 to 6 => 16.7%

In game against Protoss: depends from opponent. If he going to some kind of gateway units/Immortals - upgrade you infantry asap. If he goes for Colossus - you could delay infantry a little to get some Vikings/Thors and concentrate on their upgrades in first turn.

In game against Terran: if you see StartPort with techlab - that means banshees probably with cloak. Then you need: 1) expand, 2) EB + turrets in mineral lines. If you see opponent plays MM/MMM too: do infantry upgrades ASAP, if he goes mech play - think how to counter and if you will go with infantry - do upgrades ASAP. If no - delay them.

  • Great answer. I realize there are a ton of factors here, and I appreciate you trying to lay them out.
    – JoeB
    Commented Mar 21, 2011 at 18:09
  • Also, and the only thing I'm not in agreement with, is the double Ebay after spire scout. I need those turrets quickly, agreed, but if I'm doing well there will be no gas/minerals for all that at once, so I suppose 1 ebay, then turrets, then second if I can afford it. Anyway, great answer thanks.
    – JoeB
    Commented Mar 21, 2011 at 18:10
  • Usually, it is worth to delay few marines/marauders in order to get defense upgrade earlier. Upgrades rules and rocks the end game. Coming into mid game having 3-3 infantry upgrades is VERY important. Usually, nobody build 2 spires to get more air upgrades for mutas quickly... and very often happens you 10-15 marines are required to survive against 10-15 mutas. For sure, all you marines will die. But having +3 armor mean that instead of 9-3-1 damage they will received 6 only (instead of 13!!! - more then 50%!!!), or in case of at least 1 upgrade - 8-2 - (10 instead of 13 - 30%).
    – Budda
    Commented Mar 28, 2011 at 18:45
  • Receiving lower damage mean instead of killing 2-3 mutas they will kill 5-6! If you have medivac close.... that will be just deny agression. And you don't need to take your army back and forward trying to keep those mutas. You will keep only 10 of them on each base + mobile force of 30 of them. In this case mutas will not kill SCVs, depos... they will just fly back-and-forward losing stuff, resources, and time without any benefit.
    – Budda
    Commented Mar 28, 2011 at 18:48

I think there was a day9 daily which talked about upgrades, and stressed thinking in terms of "shots per kill" over of DPS. Hopefully someone could link to that.

When you think in terms of shots per kill between your opponent's army and your own, you will find that sometimes a +1 armor will not change anything because your marine will still take 2 shots to kill either way, but +1 weapons will mean you can 2-shot them instead of taking 3 shots (killing their army 33% faster).

Budda has done a better job giving specific scenarios. A complete chart would be impossible because you have to factor so many things - unit combinations, opponent's upgrade level. Even map and tactic can change things because you may want to be able to drop & kill their mineral line as fast as possible, rather than the more defensive armor upgrade.

  • The most important that I could remember in this case is zealot attack upgrade with +1 they have 18 damage (instead of usual 16) and as a result they kill zerlings in 2 shots. If you consider marine vs zerling - then 5 (usual damage) kill zerling in 7 shots, while 6 (+1 attack upgrade) kill him in 6 shots. This idea is in sync with what I suggested
    – Budda
    Commented Mar 20, 2011 at 23:15

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .