Absolutely! Here's why.
One of the reasons is normalization. What happens when you create changes in your campaigns, or even the strategy you use to develop campaigns, is that there is a boost to performance because you really have found a more productive way to communicate. The problem is that the effectiveness of these new campaigns, or this new strategy, wanes over time back to the norm.
In some cases the reason may be obvious. For example, your team sits down and creates great new subject lines, which boost email open rates. No one is surprised when after a short period of time the open rates go back to the norm, since people have seen the subject lines multiple times or have already responded to them. It's time for more new subject lines.
But what about when you decide to segment your list to better target customers? You execute the strategy and get a nice boost to performance. Yet over time you see your responses slowly moving back to the norm, to where they were prior to launching your segmentation strategy.
It really doesn't make sense for the effectiveness of segmentation to wear off, yet it does. This is normalization. Believe it or not, it's unclear why it happens. Possibly boredom sets in with the new strategy, or marketers don't maintain a high level of energy to not only execute the strategy, but also to create great campaigns within the strategy. Maybe they think the strategy is the answer by itself.
Other examples of normalization for marketers occur when new products are launched, when companies change advertising agencies, or when there is a significant change in the makeup of the marketing team. Each of these cases typically will generate a short- or moderately longer-term boost in performance, but inevitably results work their way back to the norm.
Change for the sake of change is a way to counteract normalization without having to go the extreme of switching agencies, changing the team, or blowing up what has worked successfully in the past. Build change for the sake of change into your company's marketing strategy. Have one team member responsible for coming up with an "out-of-the-box" campaign or strategy every month and build it into the plan. Make a list of the really new and different things you want to try in the coming year and be sure to execute against them on a regular basis, even when the things you are doing are working just fine.
And always make a series of significant changes just prior to your busiest season, as you really don't want buyer fatigue or normalization to set in just at the point you are counting on to make your year.
Another trick to use is that when you find campaigns, strategies, or tactics that work especially well, use them multiple times; but do it randomly when possible. Don't run the same successful campaign every three months on the dot, as each time you run the results will end up closer to the norm than to the great success you had the first time you took it to market. If you randomly launch the campaign, six months later, then after a single month, then in a season you never used it before with tweaks to the creative, you can slow down the normalization process and boost the reiterative performance. Note that you can slow it down, but you can't prevent it from happening entirely.
Normalization isn't your fault and some great minds are baffled by why it happens, but all agree that it does. Consider it and build your strategy around making changes for the sake of change, before results suffer.