Two Fighting Styles: Choose or Use

[LibraryOgre]

If you have two fighting styles, can you apply them both in a single round, or must you pick one per round?

For example, a 10th Level Champion with Dueling and Defense, wearing armor and using a one-handed weapon with nothing in their other hand. Would they gain both the +2 to damage and +1 to AC? Or would they have to choose?

[Frogreaver]

If you have two fighting styles, can you apply them both in a single round, or must you pick one per round?

For example, a 10th Level Champion with Dueling and Defense, wearing armor and using a one-handed weapon with nothing in their other hand. Would they gain both the +2 to damage and +1 to AC? Or would they have to choose?

The get both - providing both are applicable.

[Leon]

As long as you meet the requirements they work.

If you have done some Feats, Multiclass and such you could have a character who is Dueling, defensive, blindfighting and intercepting attacks on allied targets at the same time

[Witty Username]

Usually, fighting styles have conflicting requirements, but when they don't they can be used together.
Dueling, protection, defense, interception, and blind-fighting can all be used together (as well as the cantrip ones).

[Chronos]

You don't "use" a fighting style. It just applies.

[LibraryOgre]

You don't "use" a fighting style. It just applies.

I'm used to a slightly different definition, where styles are more or less independent of each other, thus the question.

[JackPhoenix]

You can even use two fighting styles at the same time (Dueling and Thrown Weapons Fighting), assuming you're throwing javelins or something.

[LudicSavant]

I'm used to a slightly different definition, where styles are more or less independent of each other, thus the question.

Not independent. They stack.