How do I and my business partner balance refactoring old code vs. completing the project?

Last year, I decided to start a company and develop a piece of software to offer as a service. I’m doing it with a business partner, and we’re both college students with 2-3 years of coding experience. He’s a slightly better programmer than I am and is the lead dev, while I handle the business stuff, architecture, and requirements. We’ve both written an equal share of code and are collaborating on the front end right now.

I tend to be more focused on completing the project. I like sticking to one methodology and going ahead and implementing features, even if my code isn’t the best quality and can be improved. I don’t really like to go back and redo or refactor old code, or apply new practices in the middle of a project.

Meanwhile, my partner likes to write high quality code. He constantly finds new and better development practices like Typescript and TDD. He likes to continuously go back and bring old source files up to the new and improved standards that he discovers. So far, I’ve agreed to most of his suggestions and refactored some of my own code.

This has been going on for 7-8 months, and I think we’ve spent as much time improving past code as writing new code/implementing features. I feel like there are endless improvements that can be made. The requirements are already clearly written down and both of us understand that they won’t change.

So I’m sure that the main issue here is I and my business partner have different perspectives on development. Our relationship is good at the moment, but I’m starting to get a little impatient and want to make progress with the features. I’ve suggested that I stick to the front end and my partner sticks to the back end, but he says that both of us should question and review each other’s code.

How can we improve our situation? What would professional developers do to balance delivering the project with writing good code? Would agreeing on a written quality standard help (does such a thing exist?) Both of us have never worked at a real job, and don’t know how real software teams do it.