Once upon a time, you just needed miles or segments.

Many of us saw that to reach 1K, we needed just five more segments. So we started doing multi connection flights. Voila, we reached it.

Or we needed 687 more miles. So we we fly DEN-LAX-IAD-ORD (rather than DEN-ORD). Voila.

I have 2MM status now, so I don't even try to figure out all the points and spends and miles. It used to be algebra. But now it's calculus to figure out!