Is scaling your spending too early quietly ruining your runway?

When we first launched, we operated lean. We improvised our tools, worked out of tiny spaces, and every dollar spent was strictly tracked. Then right after our first funding round, we upgraded to expensive software suites, hired too quickly, and spent heavily on premium perks. Instead of accelerating our growth, it dramatically raised our burn rate and left us scrambling before reaching product-market fit.
How do you maintain a frugal, resourceful mindset across the company once fresh capital hits the bank account?