When you are preparing to go to trial in your case always give the other party notice of your claims. The other party needs to know what you are asking for to give them a chance to do what they need to do to defend those claims.
In other words you can’t decide a week before the trial or even the day of the trial asking for new things or bringing up new claims that the other party doesn’t know about. The reason for this is you have to give the other party a chance to defend against your claims, so they can gather whatever evidence they need to defend against those claims.
As an aside if you ask for something in your initial petition for whatever it is you filed, decision making, parenting time, child support and you change your mind along the way and intend to ask for something different, it’s a pretty good idea to let the other party know as soon as you change your mind so they know what direction you are headed.