What word could you use instead of In advance?

Here are some words you could use instead of "in advance," depending on the context:

Formal:

* Ahead of time

* Preemptively

* Prior to

* Beforehand

* Previously

* Proactively

* A priori (more academic)

Informal:

* Upfront

* Early on

* Ahead of the game

* Early bird

* Pre-game

Other options:

* Early

* Previously

* Ahead of schedule

* In preparation

* To prepare

The best word to use will depend on the specific situation and the tone you want to convey.