I also have something like 15 years of serious C++ experience, but I've used it more for data processing than software engineering. While std::vector has almost

I also have something like 15 years of serious C++ experience, but I've used it more for data processing than software engineering. While std::vector has almost always been good enough for me, I've often had to replace std::unordered_map with something smaller or faster, or with something where I have more control over memory layout or serialization. std::unordered_map is not a particularly good example of things that need platform-specific optimizations. The implementations I have seen are pretty close to standard C++. std::vector implementations, on the other hand, are often really weird and rely extensively on compiler-specific annotations.