1. We all have busy lives, and not everyone prioritises their workouts. If for whatever reason you miss one of your two days (e.g illness or working overtime), you will be missing a whole muscle group out with it. So better to plan full body sessions so to lessen the imbalance. 

2. If you were to do a “Leg day” session, that could be 4-5 lower body exercises in one session. You could be so fatigued by the first 2 exercises that you struggle to keep up the intensity for the next exercises. Try supersetting an upper body move with a lower body one, to allow for more sufficient rest. 

3. It’s a bit of a misconception that you need to leave your sessions crawling out to see progress. There are more than enough studies showing that if you spread the same amount of volume over the course of a week you will actually get the same results than squeezing them all into one day. If your DOMS are so bad you’re less likely to perform well the following days.

Planning full body sessions can help prevent muscle imbalances when life gets busy. Consider supersetting upper and lower body exercises for better rest and intensity balance. Remember, progress doesn't require leaving the gym crawling – spreading volume throughout the week can be just as effective as cramming it all into one day. Listen to your body to perform at your best consistently.