What is the big deal about Big-O notation in computer science?

Question

How would Big-O notation help in my day-to-day C# programming? Is it just an academic exercise?

Answer 1

No, it really helps to know what the efficiency of different algorithms are.

If you take the time to understand Big O, every time you sit down to code a loop, you'll be thinking "How can I make this more efficient?" - which is a good thing :)