It all depends on how you learn, and how you do with tests. One thing to remember is as a qualified candidate, most of the material should be something you learned in college, so you ought to have a good base of knowledge, the CPA exam just tests if you can apply that knowledge effectively in a test environment and under the much more difficult constraint of time. 18 months is a long time, but it can go quickly given the amount of material, so strategically you best bet is to maximize your time window to pass all four parts.
For me, this meant studying BEC first, I read the book on my own in a matter of weeks and then started watching lectures, at the same time as I was watching BEC lectures I started reading the REG book. Once I had the BEC lectures finished I started on reg lectures and then went back to BEC and started making notes of things I knew I needed to know and had less familiarity with (formulas, terms etc.) I focused on the areas that Becker recommended as the largest sections of the test and got very familiar with the scoring and format. I took BEC right as I was finishing the REG lectures. I then had a month where I couldn't test so I reviewed for REG and took that. Then I had the busiest time of the year at my job tax return filing and our fiscal year end. So I took April, May and June off from studying and started back up in July with FAR. I started again, by reading the book straight through and then watching the lectures. I knew this would be a big exam so ground through it and was able to sit in November. I got my passing score while traveling overseas for work and I used 20 hours of flying time each way to read the audit book cover to cover. By this point I was incredibly tired of studying to I scheduled my exam for the last day in February and passed.
The key takeaways, I knew my study style involved note-taking and reading to master the concepts, I did very minimal MCQs and no practice tests. During the last week I would use flashcards and I created two piles, flashcards I was familiar with and those I didn't know. This way I focused on having the ability to recall terms on the MCQs I wasn't going for memorization, but rather having a general idea this allowed me to cover more material (at least in my mind) and also remember it as needed on the exam without burning myself out. This is how I have always studied so I figured it would work for me, and it did. I also left myself about 6 months for any retakes if I had needed them, which fortunately I did not.
BEC 87 Feb 14
REG 84 Apr 14
FAR 82 Nov 14
AUD 86 Feb 15