Jack of All Trades question...

[JumboWheat01]

Starting at 2nd level, you can add half your proficiency bonus, rounded down, to any ability check you make that doesn't already include your proficiency bonus.

Does this mean you can add it to things like CON saving throws to keep Concentration? (And by extension, I suppose, all saving throws, but CON's the important one here.) If so, this makes a potential character build I'm drawing up even easier to build, but I thought I'd ask without going with the assumption first.

[Millstone85]

Saving throws are not ability checks.

Weird, I know.

[Citan]

Does this mean you can add it to things like CON saving throws to keep Concentration?
You answered yourself but didn't realize it. ;)

Jack of all Trades applies to ability checks.
Keeping concentration is a saving throw.
So it doesn't apply (you know, if it did, Bard 2 would probably be as popular a dip as Warlock 2, or maybe even more :smallbiggrin:).

[JumboWheat01]

So saving throws use abilities, but are not ability checks. That is weird. Ah well, the character could still be built fine, just need to work around it a little bit.

[LeonBH]

The primary difference is, an ability check is something your character attempts/you ask the DM for it. A saving throw is something the DM asks you to do. Typically, because you're resisting an effect/getting out of the way of an attack. And yes, they both use ability scores.

[Millstone85]

The logic here is that you have utility (ability checks), defense (saving throws) and offense (attack rolls).

All are a d20 roll + ability modifier + proficiency bonus if applicable, but the game enforces the distinction.

[Idkwhatmyscreen]

The good news is that initiative is a Dex check, so you can use Jack of All trades for that

[Dalebert]

A good way to get perspective on the difference is ability checks are typically (with exceptions) active attempts to do something and typically use your action to do (with exceptions). Saving throws are automatic rolls you make to resist something and don't take any action or reaction on your part to do.

Ex: The Web spell allows for a dex saving throw when it's first cast on you or when you first step into it requiring no actions on your part. Once you're caught in it, you use an strength ability check against the DC to try to escape and that uses your action.