This is something, I just told someone, and I thought it was so simple, but most people don't do this!
Did you get a free trial of something? Not sure if you want to keep it? Put a reminder on your calendar to either review it and decide, or to just cancel it. Do it for 2 days before the trial is over to make sure you can cancel and not be charged! Because most things will not cancel or remind you of your free trial to be over. They have your credit card and will charge it!!
So, get those reminders on your calendar, you'll be happy you did!!