Neglect is the biggest downfall to anyone trying to build a balanced physique. Maybe the most neglected part of the body is the inferior (lower) part of the body. Maybe instead of this article saying leg training frequency it should say how much you should at the very least train legs.
At the very least you should train legs once a week for hypertrophy purposes.
Focusing on the very least regarding frequency is a good first step to getting into a routine with leg training. One cannot get the carriage in front of the horse which leads to getting overwhelmed. So, saying you are going to do legs 3 days a week might be too much if you are not used to training legs on a frequent basis. Getting a basic routine down on paper is important as well. Visually seeing what needs to be done will help to get things done. The discipline part falls on you though to get it done and not skip leg day.
Like any muscle group, legs need to be worked hard especially if growth is hard to come by. And if you are only hitting them once a week, going hard is important. You want your legs to remember the workout as long as possible especially going into the following week. Pain is a norm when training legs, especially the days after training legs. This just lets you know that those muscles have not been hit like that before or in a while.
This is a good thing!
Do not overthink what you are doing. Do not get “cute”. Stick to your big movements and do not worry about weight as much as form and hitting the desired rep range. Squats (front and back), leg presses, and deadlifts are awesome for building legs. Focusing more on 4-5 sets and a medium rep range can be more effective for growth. These are the foundational movements for great looking, strong legs. Ironically these movements are avoided the most. Maybe because they are not for the faint of heart.
Legs do require rest, even though they are big and strong. So, as you get into a routine of once a week and decide to work into maybe doing legs twice a week, make sure you give yourself at the very least 2-3 days rest in between training periods. Remember, when you are training a muscle you are breaking them down, when you are resting and recovering you are building them up!
Legs should not be neglected. They if anything should be the focus of a body because by training them you help out the rest of the body as a whole! Training legs help out with burning fat and building muscle all over the body. Frequency and consistency should work hand in hand in training any muscle group. So never, ever skip leg day, regardless of how often it is.