I write enough performance-sensitive code that I've gotten into the habit of calling .reserve() with a generous final size estimate immediately after constructi

I write enough performance-sensitive code that I've gotten into the habit of calling .reserve() with a generous final size estimate immediately after constructing a string or vector (assuming I'm not using a constructor that sizes it appropriately to begin with). It's hard to overestimate just how expensive repeated calls to malloc()/free() are. In the innermost of inner loops, I've been known to use a static string or vector to avoid repeated allocation entirely. Only in single-threaded code of course!