Great question. If you file for contempt claiming that the other parent failed to do X, Y, and Z, the court will look at it as one contempt. You should put them all together at the time you file because you want the court on your side so they will be more likely to find contempt. If you were to file for one specific incident at at time so that you can get multiple contempt findings, the court would be likely to find that you are acting in bad faith and can deny your motion and make you pay attorney's fees. You also want to remember that the court needs to find bad faith before they find contempt so if the other parent has a legitimate reason for not compliance, the court is unlikely to find contempt. As for the violating other areas of the parenting plan, they are sometimes harder to prove and hard to enforce. There is no time limit but if you want to go to court simply to say that the ex failed to contact you for joint decision making on education one year ago, the court would be less likely to find contempt than if it was an incident last week.
From the way your question is written, it appears that you are aware that if the court finds the other party in contempt at least two times in the past three years for failing to comply with the residential provisions of the parenting plan, it is a basis for modification of the parenting plan. If this is one of your main goals, then you want to do everything that will get the courts on your side. That means not filing for a contempt action for a minor issue, not trying to find a contempt for every single failure. Make it worth the court's time to hear the matter. If you are paying for an attorney, ask yourself whether it is important enough to you to pay the attorney's fees.