I myself am a rock/metal guitarist and vocalist, and after a rehersal (more so a concert) that can last for more than an hour and half I really do feel exhausted sometimes.
Note that this isn't my job and calorie calculators don't include hobbies.
Should one up his calorie intake if he/she is doing live performances on stage that spend a lot of calories?
Strenuous singing or an act can really get you sweating a lot, and get your heart pumping really fast.
There isn't necessarily a direct connection between sweating or feeling tired, and having spent a lot of calories, but it surely spends more than just resting.
Personaly, I prefer using a general calorie consumption level that takes into account all my activities. I have two reasons for this. First, activities increase your calorie usage over a long time, weight lifting increases it for at least 24 hours. So then you'd have to ask yourself wether to add the activity to today, tomorrow or both?
Second, it invites you to cheat yourself by giving you a larger energy budget than you really have. "Oh but I lifted weights today so I can eat 500 kcal more", and then the next day you're more hungry due to the lifting and you'll have a harder time staying strict to your energy budget.
