Everyone does it differently, depending on theirs and their children's specific circumstances. There's no right and wrong with this really.
Dd gets minimum loan - it goes on rent. This year it covered rent, next year it won't so we will top her up when the rent is due - it's paid in three instalments, in line with the loan payments.
We pay for her phone, gym membership and car insurance. The phone contract is still in our name, but the others are in hers - but I just transfer those to her monthly, when the direct debits go out.
We also pay her bills when they come in and we pay a weekly amount for food/petrol/toiletries of £60. We pay weekly, because as someone above said, the terms aren't exactly three months. I don't pay her that when she's at home, although this summer I've been generous and sent her £60 towards her food when she's been away on holiday!
Dd also works term time and a different job in the holidays and she uses her earnings to pay for clothes, gigs, make up, holidays, car repairs and prescriptions. So she does have to budge a certain amount.
I don't think she'd mind at all if we sent her the food/petrol money at the beginning of term all in one go, but to be honest we can't afford to do that!