When my partners and I began designing Flagback, a visual feedback tool, most of our time was split between the core feature(s) and the billing system.
Everything had to be perfect. We spent months thinking about every detail Paypal would have imperfectly solved. When we ran out of money, our billing system was so flexible that it could read minds and operate small aircrafts…
It’s really easy to get carried away. We never launched because our time was badly invested.
Protect your time, focus on the core feature(s) – what makes your product unique. Use Open Source for everything else. You’ll be able to reassess when your product becomes popular.