it depends, sometimes. I usually try to warm up each and every time I play, it's better for the hands I find, especially since i am still in 'nerve recovery mode' i want to cherish my recovery as much as i can. However, sometimes i get a riff or something in my head and i just pick it up. I can usually just pick up and play, but i don't like to do it like that. Sometimes i need 5-10 mins to warm up, sometimes i can do it instantly, but i try to warm up for about 20 before i play.