Lists abound about what you need to tell your children before they leave for college. But no "Top 3" or "Top 25" list can ever address the infinite worries, hopes and fears that accompany your children leaving for college. You want them to be safe but adventurous. You want them to be liked but liked by the right people. You want them to be friendly but not overly trusting. You want them to study but also have fun. You want them to miss you, but you don't ever want them to be lonely.
Sort of sounds like the same list you might have had the first day of kindergarten. Or middle school. Or high school. And the good news is whatever you told them (or did not tell them) worked. They got through kindergarten and middle school and even graduated high school. So you do have a clue about what to talk about before college. Actually a whole lot of clues.
You can tell them that what worked then will work now. The friends they chose who were loyal and good are the same types of friends they should choose in the future. The friends who turned out bad are the types to avoid. The study habits that worked should be emulated. The ones that didn't work still won't work. The loves that blossomed mysteriously will be missed. The ones that may blossom will be just as mysterious. That will all happen again.
There were classmates throughout school that didn't make it. They got lost socially, educationally -- sometimes they got lost tragically. That will happen again.
And your parenting was up and down. Some days (months, years) you were great and you knew it. Sometimes you were terrible (and you knew it). Many times you just didn't know the answers and maybe found it was best to tell your children just exactly that. That will happen again too.
Your college student needs to know who to talk to at college about: safety, courses, teachers, dining hours and where to do laundry for starters. They need to know what to do if trouble happens and how to avoid it -- campus counseling services (emotional as well as academic) are great resources. They need to know how to start managing money and dirty laundry for themselves. They need to keep learning about how to manage life.
But most of all they need to know they can and should talk to you. Let them know that when something is troubling them or something really serious goes wrong they can never go wrong by talking to you. Sure, there may be additional people and resources to utilize and friendly ears are always helpful. But make sure your student knows that you should be the first to know -- not the last.
Tell them never to avoid or delay telling you things out of fear. Delay never helps anyone. Make yourself accountable by promising out loud or in writing that you will always seek to listen, understand and advise first and get upset or angry last. Make sure you tell them (again) that you'll have their back. You always have. You always will.
So the talk to have with your children leaving for college should be about talking to you. And the one thing you need to tell them before they leave for the first time and every time is that they can always talk to you.