In very high volumes, tiny performance gains might help each server handle a few more requests - but in that case, you're better off just adding another server

In very high volumes, tiny performance gains might help each server handle a few more requests - but in that case, you're better off just adding another server rather than changing all the prints to echos or whatever ;) It is important to have scaling in mind when coding, but that had more to with eliminating 50 SQL queries per request situations - the code itself, certainly in a high level language like PHP, should be written for easy maintenance rather than performance IMHO.