Regularly

What does that word even mean? Like, it sometimes bothers me when I read instructions to something I've never owned before in my life, and they say, "change the filter regularly". WHAT THE HECK DOES REGULARLY MEAN? Furreals! It could mean ANYTHING if you're completely inexperienced! "Regularly change your toothbrush" = every 4 months. "Regularly change your bed sheets" = every week. "Regularly update your ipod" = every YEAR.