No matter how certain you are of the benefits that the change will bring to your organization, and of how much better people’s lives will be in the future, one of the best things you can do is to never say “I told you so.”
People will adapt to change at different rates and with varying degrees of ease. For the people who are early adopters — your champions and change agents — they will readily come back to you and tell you how they feel. They have figured it out and they’re going to give you ideas to keep going farther. No issues with avoiding saying “I told you so” to this group — they moved beyond needing to be shown that it would work long ago.
For the people who were not early adopters, who were frightened of what was coming, or who didn’t believe that the expected result could be achieved, when the point is reached where it becomes obvious that things have worked out as planned and their lives are actually better, they may be ready (or not!) to verbalize their agreement with the positive outcome. At this point — no matter how hard it was to get them to recognition of the positives — all you should do is smile and say “I’m so glad you’re happy with where we got to, and we couldn’t have done it without you.”
As hard as this might be, next time that person’s attitude about change could be completely different.