Beating library implementations is usually very easy since you know your use case perfectly and they don't. You need to be way less competent than them to not b

Beating library implementations is usually very easy since you know your use case perfectly and they don't. You need to be way less competent than them to not be able to do something better when you write a tailor made solution. The main reason not to do it is that it takes time and makes the code harder to get into for new hires.