With camera lenses becoming sharper, every little pore or crack in a lip seems to show up. Hot studio conditions or outdoor shoots can make the situation even more challenging. Often we wish to flatter our subjects even in a casual image. Professional models or clients wishing beauty sessions want to look their best.
Post processing in an image editing program such as Photoshop can be time consuming at best. Fixing chapped lips can be a challenge at times to get a realistic look even with a skilled retoucher. Whenever possible, I think most would agree to try to get it right in the camera during the shoot whenever possible.
Ideally, we would all like to have a makeup artist on set, however that may not always be possible. Below is a link featuring 12 lip balm products- some good and some not so good.