I have spent several hours a day for the past 25 years staring at a computer screen. So, like many people my age, I have to wear glasses to read. However, I don't need them to drive, so when I am out and about on a weekend I often find myself at the supermarket without my reading glasses. Most of the time I browse the aisles with no problems and find what I need.
But if a product is going to catch my eye when I don't have my reading glasses the product label had better be easy to read. All the important information such as brand, flavor and the product tag line should be featured prominently. There is no hard and fast rule here, but the larger you make the type the more people will be able to read your labels. And with the youngest baby boomers now in their late 40's, designing product labels for easy readability is going to become more important.