A lot of people are paralyzed at the thought of having to target a "completed" resume. More specifically, many job-seekers don't want to have to deal with a resume that needs to be adjusted in any way because it seems overwhelming and tedious. While that might be OK in certain, rare situations, you really have to get comfortable with the idea of targeting your resume for each specific position that you apply for.
The good news is that this is reasonably easy to do with a good resume. With a well constructed resume in hand, you can quickly make a few tweaks to the introductory sections before sending it off. The problem is that most resumes aren’t user friendly. That’s why it can seem so daunting to make any adjustments.
The same holds true for cover letters. You are at a distinct disadvantage if you don't personalize and direct all of your job-search documents in some manner.
My advice is this... First, ensure that you have a core resume that is easily adjusted; this is best accomplished by including some well constructed, agile introductory sections. Once those sections are in place, it won’t seem so daunting to make adjustments as you apply for various positions.