Every time you roll your own, you need to attach a future cost: bug fixes, documentation, testing, training, and so on. Your future costs can quickly spiral out

Every time you roll your own, you need to attach a future cost: bug fixes, documentation, testing, training, and so on. Your future costs can quickly spiral out of control when you implement your own solutions. Furthermore, because these are so expensive to maintain, yours will be a bare-bones version and start to show its age rather quickly. The cost of switching away from something increases over time, so inertia will incentivize staying with your minimal, custom solution while other, better solutions will become more full-featured and robust. Unless you pay the cost to keep up with the industry (or switch away from your custom solution once others meet your needs), you will fall behind. But keep in mind that others are most likely not paying this cost, so they're investing in features, continuing to outpace you in areas that matter. In short, only implement something yourself when absolutely necessary—for example, when it's a core competency, or when no current solution exists. Even a de facto solution that's suboptimal tends to be better than your own, because it will be documented, new contributors won't have to train on it, and it may improve over time. If you have to switch away from it at some point, there may be tools to automate or simplify that transition. The smartest decision for things outside your core competency is "do what everyone else is doing." Focus on innovating on the things that matter instead.