Editing Hearts of Iron (section)

===Things I wish I knew that HOI4 doesn't explain===
1. TRUCKS: Trucks are by far the single most important thing you can build after guns, cannons, and support equipment. You don't always need one factory building trucks, but you always want to switch over production if your supply starts getting a bit low. If you can afford to upgrade your supply lines to use trains, they're also nice, but trucks are a rare bit of equipment that helps with both equipping divisions and feeding logistics needs, especially if factories are tight. You should research half tracks because they give extra protection to your motorized troops in trucks.

2. Aviation: If you want to win, Aviation is a requirement. The benefits that aircraft give you are so good that you should sacrifice pretty much anything else to produce airplanes. CAS will benefit your ground troops the most, but if you must, then TAC bombers can work, as they offer better range at the cost of attack.

Abridged list of aviation types and purposes:
*[[A-10 Warthog|CAS]]: Extremely important in Europe and tight spaces. You use them to directly support any ground combat, or even hit ships but we don't advise that (any AA-bristling destroyer can ruin weeks of production in a pass). Hampered by limited range, but you can make variants with improved range the somewhat negate this.
*Tactical Bombers: Long range planning, literally and figuratively. They can do strategic bombing, naval bombing, or CAS work if your CAS can't support the frontline due to them being far away. Can be fit with jet engines unlike CAS and boosted to fuck up even line-AA if the war goes on long enough.
*Fighters: MANDATORY. You never want to lose air superiority, or your CAS and TAC bombers can say goodbye to being any kind of efficient They can also be useful in interception missions. Even in regions with no enemy planes they give combat bonuses even if one plane is deployed.
*Naval Bombers: Mostly useful for recon over the ocean and convoy raiding. Can be Meme-level rage inducing if your main fleet doomstack runs into 2000 naval bombers.
*Heavy Fighters: Mostly for bomber interdiction. A little better at Air Superiority at the cost of being more difficult to produce. Longer range gives them an advantage in supporting strategic and tactical bombers. Niche use in pacific and East Asia.
*Strategic Bombers: Are you a large power? Do you have nukes? If neither of these questions are in the affirmative, don't waste your time.
**Carrier aircraft are not worth the effort unless you have aircraft carriers. They are the same as the land variants, only more complex to build, and therefore a waste of time and resources.  

3. Specialist armor: Special armored vehicles like SPAA, SPG, AND TDs are actually slightly cheaper to build, just like they were in real life. You also retain some production on those vehicles, and combined with flexible line and dispersed industry is amazing. One may ask: Why not just use motorized artillery instead of building these big expensive vehicles? The answer is that tier one SPGs put out 34.0 damage compared to line artillery's 25.0. Additionally, they have hardness, something arty lacks. Bear in mind that building 36 vehicles per battalion will still take a while, so make sure you have as many industrial bonuses as possible and don't overdo it on the number that you need per division.

4. Concentrated Industry is a trap for major powers. It ''looks'' like a good deal, what with its boosted output over Dispersed and higher efficiency caps, but Dispersed not only still gives a fair bit of built-in output production (albeit 5% less per tier for a total of 25% less raw at max upgrades, although after modifiers it's a fair bit less), but maintains efficiency better when swapping out for upgraded designs or having to redistribute your production when you're short of one thing and have a surplus of another, gaining bonuses to efficiency retention rather than output that can be combined with Flexible Line to go from building infantry equipment to heavy tanks with as much as 80% retention. It also offers situational-but-sometimes-worth-it bonuses to resist enemy bombing and to switch back and forth between military and civilian factories.

*Caveat: Concentrated industry can be worth it if you're playing a smaller nation that's going to be fighting a war right off the bat(Ethiopia) or a country that has trouble banging rocks together to make factories(Liberia) and that cares more about pumping out as much shitty 1936-era infantry equipment as possible than putting together a modern army or upgrading literally ever(Yemen, Oman, Saudia Arabia) or go for the meme-level discount for rifles when playing Mao and raise 20 million CCP drone riflemen in 3 years.

*On top of that, never play any of the above unless you hate yourself or have a life. It's a military wargame, not an economy and infrastructure simulator.  

5. Support companies: Good, but don't concentrate a dumb number of them in your line infantry battalions. Hospitals, Engineers, and Artillery work just fine early on, though you'd be forgiven for adding in support AT companies. Leave the other stuff for Armored, mechanized, or special forces. Later game you'll want Line artillery to replace the support artillery and support AA because planes are the new meta. Keep in mind this isn't always a rule but a general guideline, and AA is always the poor man's [[Bolter]] to add that penetration force and hurt enemy plane production.

6. List Building: HOI4 is a lot like 40k list building in that you need to tailor your armies to what industrial, military, and resource strengths you have. Brazil has a decent supply of Aluminum and Rubber, so you bet your ass you're gonna be heavy on the air force. Compare this to Iran or Iraq who have fuck all but oil. This means you'll need to consider having recon and radio companies just to make your basic infantry worth anything, and you can forget about having any real kind of air force. In single player at least: in Multiplayer every player coalition is meta-wise under free trade and buy stuff from each other so it's often a question of using your population and designs fitting the battleground.

7. Occupation: Make sure to change your automatic rules when occupying to be secret police and cavalry. This is a minor thing that is never explained in the tutorial whatsoever and is easy to miss, and it makes a huge difference. Add military police support(after setting width of the template max) once you bloat and can afford the IC and aluminum.

8. Micromanaging: Do it. The AI can be dumb as fuck when trying to wage your battleplans, so if there is something you want to not exist, grab a ton of armored divisions and initiate Kursk 2.0. Sometimes in order to get a campaign moving, you'll have to pause the entire battleplan and manually order individual units to attack targets(especially outside wide plains of Eurasia). This is ok and to be expected. Some campaigns take forever to finish and that is how it should work.

9. Invasions: You typically want to have some divisions to break through the enemy line, mostly armored and motorized. These should be no more than two regions wide. The Mechanized make the breakthrough, while the motorized get into position and delay counterattack so the rest of your army can properly encircle the enemy. The rest of the front are your cookie cutter infantry divisions that protect yourself from counterinvasions by the enemy, and should push into the enemy set to "Cautious" battle plan execution.