Time and Money.  
Both are scarce resources.
Money depletes quickly.
Time depletes, comparatively, more slowly.
Before you spend your money, spend your time.
Determine if your time is resulting in a loss or a gain.
Then, when you discover where time is well spent, spend money on it, so that you don’t need to spend more time on it but other people or resources can.
Money can be replenished.
Time can’t.
Before you spend your time, be very selective.
Waiting is a cost, too.
Time is always ticking and not using it is wasteful, so pick wisely, move aggressively, find what works, and use money to expand it.