Workout videos

I'm fairly new to this whole exercising thing. I've done a few videos on here. I'm wondering if it's beneficial to keep doing the same workout every single time until I've got it mastered before moving on to different ones, or if it's better to mix it up each time. I go to the gym 2 days a week where I do a full-body workout with cardio and weights and I'm using these videos to supplement during my non-gym days.