Most business owners I've found have a fear of marketing,  much less branding. Most people do not realize or understand the  importance of branding. Branding matters, messages matter, &  tag-lines are something that can have a huge effect on you business. A  successful tagline's lifetime is almost infinite. The only time a  tagline would need to be changed is if there are pressing reasons to  change the core message. There can be reasons, for example if there's a  change in your company's focus, or the competitive environment in which  you work; then you'd need to change your tagline. Although ideally you  would never want to change your tagline.(that will only confuse people)  If you must change, change only your "Image" to help consumers meet  where you are today. As challenging as it is to create a strong tagline,  it's all too easy to craft one that fails. NEVER be generic. Remember,  your brand in general and your tagline, almost more than any other  piece, should be as specific and emotive as possible to highlight the  connection between an individual and your business. Generic language is  deadly! Your tagline should show the value of your business. Your  marketing should never raises more questions than the answer. Do NOT be  generic. Be specific and distinguish your company from the others. Never  indulge in or plan uneasiness. Avoid introducing ambiguity into your  branding. Avoid poor word choices. Only use ONE tagline at a time!!  The  best way to confuse and alienate your audiences is to send out multiple  messages at the same time. Unless consumers are hearing consistent  messaging from your business, they are not going to recognize you in an  instant. 
To be honest that is all you truly have. You have an instant to  attract & keep their attention. It's imperative your message has a  generalized positioning value. If your message doesn't have positioning  value, if it is just a descriptor, it is a waste. That is really key,  the most important "do." You want to make sure you make your tagline broadly accessible and memorable, avoiding jargon and acronyms. Make  sure you can be recognized at a glance, that your company is memorable.  What is it that is so important that people want to repeat it and that  they can not stop thinking about. You ultimately want your company to be  seated not only in the brain, but in the heart of your consumers. 
