It’s called having a strategy, and realizing that the best way to achieve your goals was to pursue them in parallel, rather than serially. It did help that my main ships at the time were an exploration Hauler and my Cobra Mark III, so it wasn’t like I had thousands of modules to do. At the time, credits was still scarce enough that BGS work consumed most of my income, and I really wasn’t in a hurry to move to larger ships because I still prefer how smaller ships handle in Supercruise.
It also helped that my raw materials bin was overflowing due to enjoying flyving the SRV, and prospecting on planets as part of a group effort to plumb the secrets of the Stellar Forge… at least until Frontier moved that function to the detailed surface scanner.

And of course I was busy collecting other things, just in case I needed stuff for synthesis. So by the time Engineers dropped, I had sufficient stores to get my two workhorses to G3 and G4, with three G5 modules IIRC. And when those bins filled up again, I’d G5 whatever I could, and use the rest to improve the G3s and G4s. Because G3s and G4s were
highly underrated under the old system.
Fun fact, some of my G4s, thanks to random rolls, were actually
better than many G5s, and some G3s better than many G4s, and approached G5 quality occasionally. So some of those low quality G5s were stored to be used in new ships, which I started acquiring rapidly post-Passengers, once income inflation reached ridiculous levels. It also helped that the Diamondback Explorer (and before that, the Asp Explorer) shares a FSD size with
so many medium and several large ships, so when I acquired a new ship, I always had a G5 (or occasional super-G4) FSD waiting, along with power plants, weapons, shields, etc. It’s a trend that continues to this day.
I will admit I never bothered to G5 my thrusters
until after the Passengers update, falling short of Prof. Plain’s unlock requirements. My ships had some pretty sweet G3 thrusters, though.