Internalising what's a reasonable business expense compared to personal expenses is a skill I feel I've only fairly recently developed.
It's super important to consider the human cost and opportunity cost of each decision, and it's scaling characteristics.
Eg: spending $20+k on a ci system like circleci, GitHub actions, whatever might feel like a big purchase, but if you consider that split by the number of developers using it, their salaries, and that in general it scales with your head count rather than user count suddenly it's pretty attractive.
On the other hand some other seemingly small (unit) cost that applies per user of your product might be worth optimizing/eliminating as that can have a big impact on your margins - but even then you need to balance it against opportunity cost. We could increase margins by x% with y investment, or increase revenue by z doing something else where the delta of revenue outweighs the better margins.
Basically it's a big juggling act involving numbers that we're not used to dealing with in our personal finance and you need to ground your thinking in terms scaling characteristics and the companies overall revenue/burn to appreciate what actually moves the needle.