I guess I have reached some kind of milestone in Terracore now. Since a while back I have stopped purchasing scrap to buy things. Even though it is hardly going to break the bank.
How much can I increase my stats really just from what I get in the game. From a pay-to-win perspective I doubt you will ever make your money back anyway but from a number-goes-up perspective, it might be wise to get a solid boost until you have your first 100 - 200 or so Damage and Defense.
Find that sweet spot. Since everyone mainly uses the same interface it means you can quite simply determine a good Engineering value to almost never be attacked by remaining under the general max.
From there it is simply a case of click the button every 4 Hours or so and pick a stat to focus on.
As for my "milestone", I spend a week or two just adding to Stash and Favor, so now if I like I qualify for all the Planets.
The most economical use for scrap now is still to just dump it into stats and you will be hard-pressed saving a few days and then wasting that on 4 flux for the maximum planet.
From a Drop Rate perspective though I think the 2 Flux Planet is the best one to target.
I do not like quests, so no opinion.
I think I am fine with where my Defense / Idle Stash value is at since with my Defense I tend to get to 25+ Scrap before needing to really claim in the 4 Hours.
So I will focus now on getting my Damage to 300+