Writing something new comes with tremendous future cost. 99% of the functionality will be pretty quick to implement. But 3 years later, you'll still be fixing e

Writing something new comes with tremendous future cost. 99% of the functionality will be pretty quick to implement. But 3 years later, you'll still be fixing edge cases and you'll have to keep the documentation up to date if you ever want to hire other developers to work on it. Writing something from scratch just because you want to understand it is fine. But you should think long and hard before actually using the new thing you just wrote in production code.