Point(s) of inflection in career games?

[Aragosnat]

Docking port is a big one. As like others have mentioned. It makes returning from other planets/moons as well as doing multiple science for one planet or moon easier. Solar panel and science parts are great as it let me unlock the rest of the tree quickly if I don't want to use contracts to fill the tree out.

[Captain Vlad]

Nuclear engines were big for me, but honestly not as big a deal as landing gear.

[Nemrav]

I always make a bee-line for fuel-lines, struts and possibly solar panels... Otherwise I quickly get to the point where my rocket is too wobbly to get any further....

[James_Eh]

No offense, but you really need to study rocket design. My "standard" non-nuclear probe (including booster, probe, and full stock orbital instrument suite) weighs in at 6 tons and only costs 48k. It doesn't need a big booster.

Well, I'd be a little offended if I didn't know that sometimes what I am sure is correct winds up being only sometimes correct... I'll send you a picture of my usual wee mid-game probes and if you wouldn't mind maybe you could throw me suggestions about how to get them on their way in a cheaper fashion.

[DerekL1963]

Well, I'd be a little offended if I didn't know that sometimes what I am sure is correct winds up being only sometimes correct... I'll send you a picture of my usual wee mid-game probes and if you wouldn't mind maybe you could throw me suggestions about how to get them on their way in a cheaper fashion.

No problem at all, or you can ask/post in the Gameplay Questions & Tutorials forum. Always lots of folks willing to help.

[Madrias]

Solar panels, basic aircraft parts, and fuel lines solidify Career for me.

Solar Panels keep my interplanetary craft fully powered, as well as allow for the use of probes. This means cheap, easily renewable science, and opens the path to ion probes and rovers later on. Without power, one cannot expect to get anywhere.

Airplane parts allow me to steal the sweet science from Kerbin, as well as opening the path for my atmospheric landers, meaning Eve and Laythe are now open for land, plant flag, and return missions. Yes, I have a spaceplane that can, with a bit of trickery, leave Eve. I just leave 90% of it behind as debris there after reaching a critical altitude.

Fuel lines allow complex ships that can comfortably sail out of the atmosphere. This means no longer needing to worry about getting fuel out of my drop tanks, carrying spare engines, and multi-engine turbojet flameouts. Which means I can comfortably use spaceplanes to leave the air behind and travel through space.

Sure, there's other parts that are essential to have, but those three main ones allow me to pretty much ignore the rest of Career mode as "unlock part, go do science, make rocket." and play it as an unlockable sandbox mode.

[ArmchairGravy]

Solar Panels-->Science Equipment-->Skippers-->Nuclear engines. These are my four key technologies. Everything else is just points for style.

[SkyRender]

Given that you can legitimately max the tech tree and get absurdly high funding levels without ever leaving Kerbin's SOI no matter what you set the difficulty to, the LV-N is less critical than it could be. The most critical, of course, are science instruments (and the solar panels and science lab that you get on the way to unlocking all of them). After that, fuel lines and struts. Then docking ports. Maybe probes. Everything else is just icing on the cake. My ideal Mun mission requires no more unlocked than all science instruments (and solar panels; again, unaovidable on the way to those parts anyway), a lab, a probe core, fuel lines, and docking ports. It can pluck the science right off every single biome in all situations and basically max the remaining tech tree in that single mission as a result. And that's not even accounting for contracts, which are so broken at present that you just need an orbiting craft with a thermometer, solar panels, and an antenna to get infinite funds, reputation, and science (albeit in small doses).

[SorryDave]

I like to unlock the tech tree before going into orbit using just contracts and admin strategy. The turning point is usually about the time I unlock all the 90 point techs. Usually higher science and dollar contracts start rolling in, but this may be more from the reputation.

[LethalDose]

Nuclear engines were big for me, but honestly not as big a deal as landing gear.

OOOOO good one. I hate that the gear are so far away from the jet engines and other reasonable plane parts. Every career mode, i'm all:

"WOOOO JETS!!! now to time add the landing geaaaaaaaaaaaaaaaaw [12 min stream of obscenities redacted]"

It's, uh... frustrating.

[FlyingPete]

It's quite handy to use contracts to scam companies out of their experimental parts. I got a 'test LV-N' contract, so immediately sent a fleet of nuclear tugs to my station for later use. I did eventually complete the contract.