It really is a case of how long is a piece of sting and depends on a many factors. I.E. how much maintenance loan will they be entitled to, how much is the rent, is the uni area a tourist area with a higher cost of living, how much could you afford to help them out and how would doing so impact on your life now and in the future, how academically able are they (do they have dyslexia or a disability) and would they really struggle if working part time alongside their studies, what are their expectations currently do they spend a fortune frittering away money on beauty products, tech, clothing, socialising or have they more realistic expectations that the world doesn’t owe them a living etc etc etc.
The best things you can do for your DC before Uni in my opinion unless you are extremely wealthy and money is no object is learn them to cook, how to shop, meal plan, budget, the value of money and how to keep a kitchen, bedroom and bathroom area tidy and hygienic etc etc.
DS is going to Uni in Sept he is fairly academic and looking at high end uni’s that have a tradition for attracting the wealthy etc. He will only receive the minimum Maintenance Loan but we have told him we will help out but he will still have to get a summer job and live quite frugally whilst at Uni and also work whilst he is there and in the holidays which he is fine about. We will work out a budget of what we can afford, make sure his rent is paid and we will make a sizeable contribution (as is expected) but he will still have to budget and work part time when he is there and in the holidays. But he is looking forward to the experience, having fun and working hard.