Go to shops in sector 1 & 2?

[Snow Job]

As a general guideline, if I'm playing on normal difficulty with an average or strong ship, I try to build up a big pile of scrap and spend most of it in a Sector 2 store.

Weak ships are different in that they always need to shore up critical flaws as fast as possible, which involves either delaying a shopping trip for quite a while or rushing into one. Hard mode is something I don't have enough experience with.

I'll only go to shops early on if I have ~50 scrap, unless I really needed the fuel.

50 scrap is too low, IMO. I try to have at least 100 scrap (including the sell price of spare equipment), 150+ being even better, before going into a store. Being able to buy only one good module when Santa Claus is in town really burns.