We made a few mistakes here and there but @lordvdr is the son of an opinionated accountant who gave good advice. And we managed to only live for the moment until we were about 23. Then we had to grow up and start pretending that we expected to live to spend our savings.
He has a plan. He has a budget. I only buy books and, rarely, yarn, without discussing those purchases with him. And we can afford to take trips and game and goof off because we prioritized saving up for them before spending on them.
Why did we stop being spendthrift? A tsunami of things but in my case, unexpected health expenses and the sudden realization of needing to plan for a future Big Expense. We needed savings and stability and we got good advice that pointed us that direction.