Should a player make a roll for things like:
He is travelling and wants to play a flute
Wanting to carve a goblin's teeth as a trophy
Wanting to play on a drum that he found
Wanting to split through of a captured enemy
or can they be considered as automatic success?
DMG 237 explains this nicely:
When a player wants to do something, it's often appropriate to let the attempt succeed without a roll or a reference to the character's ability scores. For example, a character doesn't normally need to make a Dexterity check to walk across an empty room or a Charisma check to order a mug of ale. Only call for a roll if there is a meaningful consequence for failure.
When deciding whether to use a roll, ask yourself two questions:
- Is a task so easy and so free of conflict and stress that there should be no chance of failure?
- Is a task so inappropriate or impossible- such as hitting the moon with an arrow-that it can't work?
A simple rule of thumb is this.
"Are they attempting something that is challenging, but possible? Is there a consequence for failure or a limit on how long they have to achieve it?"
If yes, then call for a roll. If not, then do not.
Making a Flute make noise is not challenging. If he just wants to play it and isn't trying to impress anyone or accomplish anything, then no roll is required. Likewise, banging on a drum is easy. Scratching marks into teeth is easy if you don't care about how nice it looks when you're done.
If something is possible and you have no rush on accomplishing it, you don't need to call for a roll. If you take a locked chest with you and the Rogue says he's going to try to pick it while you travel...you only call for rolls if you care about how long it takes him to pick it. Otherwise...if he could roll high enough to unlock it...then he unlocks it. If he can't roll high enough to unlock it, then he doesn't. No rolls necessary. The assumption is he kept trying until he got it...there's no reason to make the player actually go through all the motions of that unless they want to. (In older editions, this was actually a rule...called Taking 10 and Taking 20, representing how long you were willing to dedicate to working on something)
On the other hand, performing an instrument in front of a tavern to try to impress them into giving you tips or to improve their attitude towards you is a challenge. Trying to carve an ornate pattern into the teeth so you can sell them as trinkets is a challenge. Trying to mimic the signal patterns of an orc clan on a set of drums is a challenge. These things should require a roll.
And to speak to time...If your players are, for example, trying to crack the code on an encrypted document, you allow each attempt to take a certain number of hours, and the contents of the document are time sensitive...then you would call for rolls.
On the other end of the scale...lifting a castle wall off the ground is impossible. Again, you do not need to call for a roll, because it doesn't matter what they roll, it's not going to work.
A general rule of thumb is a check is not needed if failing has no consequence, and it can be attempted an arbitrary number of times.
This rule is overtaken when the action performed is important to the plot, or has hidden consequences.
Your examples:
he is travelling and want to play a flute No, playing the flute has no meaningful consequence, and you can attempt it many times.
want to carve a goblin's teeth as a trophy Yes, you only have 1 tooth, and failing results in a bad product.
want to play on a drum that he found For the same reason as the first, no.
want to split through of a captured enemy Yes. Failing this may have consequences. positive or negative.
Why spend most of the game asking if a character can walk and play the flute when that same energy can be used to slay bad guys?
– BanjoFox Jul 19 '17 at 19:38