When should you update your company’s look? On one hand, it’s important for all your marketing pieces to have a consistent look but it’s also important that an advertising piece changes in some way (each time it’s sent out), because you don’t want the reader to look at it and think “I’ve already seen that”. Any ad you create has to be “similar” enough to previous work to maintain your brand continuity and at the same time “different” enough to make the reader recognize it’s something “new”.
It’s very hard to know when to change your campaign. Many big companies change their campaigns annually or semi-annually, but sometimes they’ll stretch that time out if they’ve hit on a winner. If you decide to keep your existing campaign for a while, don’t think that means your ads and brochures will never change during that time period. If your driven to maintain a consistent look & feel for your advertising, that’s great! Just be sure to make some [design] changes that are quickly & easily identifiable, to ensure your readers don’t think they’re looking at the same pieces they saw last year or last week and to make sure they don’t “glaze over” your ads thinking they’ve already seen them. You want your clients to recognize your brand but not get bored with it. Keep some consistent, easily recognizable ad elements while changing content and other things like photos and headlines to get both the benefits of a consistent ad campaign along with ads that can attract & keep the attention of your clients.