unless im on a soldier and im confident in his ability to hit the guy on me with his next rocket its pretty much always better to just hold it and do 1080s with ur mouse

It depends, as always.

If you are in the middle of nonwhere and 1 player makes a play on your med, risk dropping it.
If you are being pressured by their whole team, why haven't you used already?
If 1 player makes a play, but you are close to the choke (where the enemy is around the corner), it can be argued that it is best to pop it if it will actually save your life. You can still manage to use the last half of the kritz to do something useful. However, you should use your judgement to determine if the kritz will actually make a difference in saving your life or not.

Don't pop, save for more ideal sccenario. Situational though where sometimes popping is the right choice but not often.

Drop it don't pop it
words to live by

yo it's all about the stats, people will see that "dropped" column

If you think you're going to die, or you think you can get a key pick, use it.

If you think there's a chance of you getting out, hold it and hope for a surf.

Pop it. There is more of a chance of your heal target one-shotting the attacker, plus if you drop it, respawn times ensure that you will be at an even greater disadvantage. Always pop so your chance of living increases and you can get heals to your team, regardless of advantage.

If you are going to die it doesn't matter anymore, the only reason to use it are stats.
If you are not going to die there's no reason to waste it.

Assuming that you can't perfectly predict wether you are going to die or not i would follow these guidelines:
You can survive the next shot -> hold
Whatever player is trying to kill you would die before he can shoot again if the next shot hits well enough -> hold
You don't think your pocket is going hit anything -> hold and hope for a miracle surf
If none of these situations are given you should pop.

The only situation that justifies popping kritz is when using it could save you.
Example: A soldier bombs you, he is definitely not going to die from one rocket, but you would die if he hits one rocket. If you use the kritz your pocket might be able to kill him in time.

I would pop it regardless even if it's situational. A live medic is more useful than a dead medic.

You shouldn't be in a situation to drop krits, that shit should be popped the second you get it and everybody should be in position ready to use it by that time.

If you're not, just remind yourself that the quickfix is no longer a thing and there's no benefit to defensive kritz and that you've probably made a poor unlock choice.

The only reason to drop kritz is by mistake.

You shouldn't be holding onto kritz for more than 15 seconds or so, as your team NEEDS to use their advantage before he enemy gets uber or kritzes on your team. If you are holding on to kritz dropping it shouldn't be a worry so much as team coordination.

It's not a drop because it's kritz (Pledge and vanillatv)

You have to make a judgment call on whether or not you're going to die and whether or not popping kritz will save your life.

If you aren't popping kritz as soon as you get it, you're doing it wrong. Normally you only have a 15 second window to use it.

Obviously be in position before you do but my point is get into position as you get it.

This. I find it rare that I get bombed when I actually have kritz. Usually once you have it there's only a few seconds until you should be popping it.