Random Workouts

I have a couple of off days from my current split and usually dedicate those to rest/recovery and eat a lot more. But lately, like today which is supposed to be an off day, I might just go to the gym for 30-40 minutes and train a bodypart just because I feel like it.

Basically I woke up, then a few hours later just FELT like training forearms/calves, even though my routine didn’t dictate it. I feel that this is a good way to get a bit of extra growth for certain stubborn areas. Anyone else tried this?