I probably have, without particularly prioritising it. Ok, perhaps I should have said "overly caring about performance". Of course I have used built in function

I probably have, without particularly prioritising it. Ok, perhaps I should have said "overly caring about performance". Of course I have used built in functions in languages that take advantage of this when searching or sorting - but no, I can't remember a time when I had to get into the nitty gritty of low level performance enhancement, unless it was in a coding challenge of course.