Yea I plan to install a profiler on my machine when I get to the optimization phase of the project. I am still just plowing through as much code as I can to hit my self imposed deadline. After I have the entire engine with all functions writen in the original design then I plan to go into the phase of profiling everything. I think if I get caught up on that now I'll spend too much time disecting code when I should be finishing the project lol.
It is best to use a profiler to find such cases, rather than optimising on a hunch. Short of that, however, go for whatever makes your job as a programmer easier (eg avoiding code duplication).