Yes planning is very important, especially for a complex task. You'd be surprised to see how many teams just jump into doing formal without much planning and as a result fail to see the benefits of formal and fail to adopt it successfully in the verification flow. That's why we have been emphasizing on the importance of formal test planning, we talked about it in our DAC Insight Tutorial session and do in all of engagements. We would love to see every project using formal being successful, it has to start from good planning.
This is funny Max. Even when I was working as EVE China's Country Manager (EVE is a French company as you know), I had to present a big plan on what I would do about setting up the subsidiary in China, how to engage with Chinese customers, how to market our products etc before I was given the job. So even the French like to plan :). Unfortunately I didn't plan for the Synopsys acqusition LOL.