Hand sanitizer does not completely replace washing your hands with good old soap and water

Slathering your hands in alcohol gel is a great backup plan, but it's not a substitute for a sink. Hand sanitizers kill a lot of surface bacteria, but they leave the dead bacteria and physical dirt sitting right there on your skin. They are also entirely useless against certain nasty pathogens like Norovirus. Soap and water physically bind to grease, dirt, and microbes, violently washing them down the drain.