The concept of upgrading
An upgrade is an item researched in the arms lab (this little rant will not touch non-arms lab upgrades, which cannot be quantified as easily) - it takes effect after its research time (60/90/120) has expired. The price for any upgrade is paid at the start of research.
The upgrade types
Damage upgrades :
Add 10% damage to any weapon used, excluding welder and knife. Does include hand grenades and mines. Does not include turrets of any type, siege or sentry.
Armor upgrades :
Adds 20 armor (45/65/85) to the starting and maximum armor values of a marine. Can be updated in the field, but the marine will retain his relative amount of armor (meaning a marine with 5% armor will still have 5% of his maximum armor).
Catalyst packs :
Are considered a level 1 upgrade for research times and costs. Cost an additional 4 res per drop in the field. Their effect is to enhance the speed of any action a marine performs - welding, building, running, shooting. With the exception (!) of reloading.
The logic of the "must upgrade" doctrine
To just put myself into the position of the devils advocate for a moment, let me explain the thought process found behind common consensus among most players. It is said that upgrades are effectively very cheap, because the cost is a medium-sized one-time fee exclusively and after that comes free on every respawn.
It is said hence if marines respawn 80 times with an upgrade that cost 40 ressources, they've paid a mere 0.5 ressources per spawn - or in other words, gotten an advantage very cheap.
What then, is wrong with this?
Its amusing really, to say the least, to see a whole slew of otherwise likely intelligent people make a mistake you commonly see in elementary schools, while solving word problems. To answer the entirely wrong question - nobody asked how cheap an upgrade can become in an infinite game, but how cost-efficient it actually is taking every conceivable factor into account.
To make it a bit easier to see, lets look at the efficiency of a weapons3 rush. You begin upgrading Weapons 1 at 1:30 (You've researched Armor1 before, because you're not a complete moron). Weapons 2 at 2:30, Weapons 3 at 4:00 and have completed your research at 6:00. You've spent 90 ressources on these upgrades, including a major chunk of spending at the most critical time, 4:00.
An average game will last another 6 minutes, and its probably fair to say your team averages ~5 deaths/minute. So out of weapons 3 alone, you paid ~1.3 ressources per spawn. This is not counting that upgrading to weapons 3 likely gave you no tangible advantage that late in the game. This might not seem like too much, but bear in mind these are optimistic calculations for upgraders - and already we've got a 250% increase in actual cost of upgrades over what common consensus would like to tell us.
Is that all?
Oh no. The fun has just started. Now we've settled that games are not infinite, and even if this were a game of boring statistics upgrades would not be the end all of commanding. The actual counter-incentives to getting upgrades are yet to come.
Time of spending
We all know starting ressources are not unlimited - and the start of the game comes with alot of time-intensive researching options (AA, MT), ressource-hungry expansion and the necessity for infrastructure (IPs, Armslab, Observatory or even turrets [Haha, just kidding.]).
So as a necessary evil, I for example cannot afford to deny aliens restowers better with 2 shotguns, because armor1 is fairly mandatory for my marines. Doesn't seem too harsh so far. But lets assume you've got Armor1 and Weapons1, the most attractive upgrades as far as cost/research times go - and want to upgrade to Weapons2. Those 3 ressources spread amongst an optimistic 5 RTs took 30 seconds to get - this might not seem like much, but at this point it is 20% of the game. Upgrading now can put off for example a PG network, an advanced armory or 3 shotguns - all for receiving the upgrade precisely at the 4 minute mark.
This is again a common mistake. A light machinegun does not give a damn that its upgrading, it will only deal the damage of its current level. Hence marines are still fighting the games deciding battles with W1/A1, and finally fighting Fades with level 2 LMGs while you upgrade to L3 weapons. They could on the other hand be using W1/A1 Shotguns from 2:30 on and not just owning up the early game but barely noticing the lack of an extra 1.7 pellet damage. Which leads us to our next point.
What effect they really have
Not enough people are currently aware that while in theory, adding 20% more damage to all my marines would make them 20% more effective, that isn't close to true. The effectiveness lies solely in the way damage is dealt, not in the height of the damage - an LMG retains its CQB weaknesses at level 0 and level 3, and a Shotgun has its tremendous contact damage at level 0 or 3.
Moreover, the majority of non-structural targets that you will end up fighting in a match of Natural Selection tend to be Skulks. A damage upgrade does not help connect bullets with a Skulk, it just lowers the required amount by up to 2. Here a table taken from the nonoobs.com damage calculator, on how many bullets it takes to kill a Skulk :
Level 0 LMG - 9 - 10 - 10
Level 1 LMG - 9 - 9 - 10
Level 2 LMG - 8 - 8 - 9
Level 3 LMG - 7 - 8 - 8
The additional numbers are the bullets required for multiple-hive Skulks. Nevermind that you might as well throw your LMG in the trash in that case, because they'll be leaping, Xenoing and using Celerity, but its still nice to know. More importantly, notice how Weapons 1 has no effect to talk of on Skulk vs Marine encounters. In other words, its exclusively a prerequisite.
A bit simpler now, the effect of armor, in Skulkbites required to kill a marine and his leftover HP before the fatal bite.
Level 0 - 2 (75 HP)
Level 1 - 3 (40 HP)
Level 2 - 4 (5 HP)
Level 3 - 4 (44HP [32HP 6AP])
The case here is a bit different than with Weapons, where upgrading below 2 is distinctly unattractive unless you're using shotguns or better. Armor1 is definitely the most attractive upgrade - leaving your marine with his fair share of hitpoints after being bitten twice. Upgrading beyond that becomes a bit cumbersome - Armor2 in competitive play with friendlyfire will seem a dubios advantage, seeing as how you survive the additional bite with a mere 5 hitpoints. Going all the way to Armor3 not just takes the majority of the game, but costs a chunk.
With that in mind, making a decision in favor of upgrades becomes alot harder to justify. Yes, all your marines will have a slight statistical bonus 2 minutes later if you upgrade to weapons 3 - the alternative being to hand out a squad of 4 shotguns, research motion tracking, advanced armory or any other of these options at the deciding point of the game.
We just have to face it after a while, that the goal here is not to plan for drawn out turtling matches in which you'll be able to cost-efficiently exploit your upgrades. The objective is primarily to kill alien hives, and secondarily ressource nozzles, chambers and aliens themselves - and upgrading does not go very far to aiding that objective. Prioritizing it will even hinder that, and hence lead to mostly turtling matches - which in turn, re-assures the user of todays common consensus that his strategy paid off, when in fact it was his downfall.
Good game. :rolleyes: