When you prepare a marketing plan, you must analyze your company's past performance as you get ready to move into the future. What marketing strategies and activities were most successful? What didn't work well? What should you change--and what should you not change?
A high-performing brand will rarely make major changes to its visual presentation--with good reason. Once you've built equity in a brand and customers know what it looks like (the word(s), colour, typeface and so on), any significant change must be carried out carefully to avoid disrupting the continuity and confusing customers.
For example, look at the Tesco brand in 2004 and in 2010. The brand looks the same, although the phrase "every little helps" was under the brand in 2004 and today it's at the bottom of the home page.
The Waitrose brand in 2010 looks very much the way it did in 2004, although not identical. Similarly, the Sainsbury has brand changed little from 2004 to 2010.
Of course, past performance is no guarantee of future performance, and brands must change with the times, especially when they want to change their targeting. Walmart recently completed a major change to its US visual brand presentation, for example, to give it a friendlier, more modern appearance. Compare 2010 with 2004 and you'll see the difference.