It's true that it's more expensive to do the work later, but you also have way more resources later; in my experience the second term increases faster than the

It's true that it's more expensive to do the work later, but you also have way more resources later; in my experience the second term increases faster than the first one. Every day you spend wiring up infra is a day you're not iterating on your product, and from the accounts I've seen, most startups fail because they run out of money before they find PMF, not because they later got bogged down refactoring their V1 architecture. I advise keeping architecture as simple as possible at first by building a monolith (or maybe FaaS if you're really doing throwaway experimentation), and keep refactoring it until your domain knowledge has solidified and it's clear where your service boundaries actually are; it's very unlikely that you'll get the service split correct the first time if you do it too early.