Some of these exemplify "premature optimization" and will clutter code with no discernible benefit. I remember some days ago, in the days of PHP, there were heated debates about whether or not using single or double quotes for strings makes code faster.
As with most development, use good practices. But then at the end of the day, profile your application to find the actual bottlenecks.
As with most development, use good practices. But then at the end of the day, profile your application to find the actual bottlenecks.