As a parent at these events, you rush between subject tutors to hear formulaic information, usually about where your Jimmy is in terms of the curriculum. Too slow to secure an early appointment, and you may be dealing with a teacher who has spoken to 25 parents before you, and is beginning to lose the will to live. If Jimmy is doing "just fine", you could be in and out in a minute, none the wiser. If Jimmy is a problem, you'll be urged to make another appointment anyway.
Fee-paying parents are ruled by the bell - presumably so no one will sue if kept waiting by the parent ahead talking overly long about Jessica's problems concentrating. Then, mid-flow, it's "ding ding", thank you and goodnight. The state sector puts less emphasis on time-keeping, so if Jessica is your child, you can sometimes hijack the time to talk it through. Be the one waiting your turn though, and it could be a good 20 minutes before you get your bum in the hot seat.
For teachers, it must be a long evening of trying to offer good news, and the parents you really want to see never turn up anyway. Then you get the odd bombshell - the parents of Dan, who's been behaving like a monster in class, reveal impending divorce, and didn't you know?
"It's good to meet the parents of children you are teaching," says one head of year tutor. "You find out things it's important to know," agrees a headteacher. That's as it certainly should be, but it's not enough to keep abreast of your child's progress.
As always, the problem child gets the most attention, but it's the plodder, the average child, who can lose out. You are reassured she is doing well, but time is too short to find out that, with a little encouragement, she could move from a D grade to a much more valuable C. "Rachel is doing fine" leaves you worrying that perhaps the English tutor isn't paying Rachel enough attention. "Rachel's English teacher says she is doing fine," coming second-hand from a form tutor is even worse. It's like Chinese whispers.
"But," you say, "Rachel hates it and dreads the lessons", and the form teacher has to go back to the English teacher to find out why.
Heads too must be questioning the value of parents' evenings, because schools vary widely in their policies on parentteacher communication. Many are introducing new schemes - such as action planning days - because they realise the current set-up is no better than the surgery of an over-stretched GP.
The GP analogy isn't way off. Psychologists have likened parents' evenings to a doctor patient scenario - the teacher gives the professional diagnosis and the parents listen attentively. They assume the right to control the meeting and parents find it difficult to challenge.
Ironically, several sources, not least the Department for Education and Skills website, suggest questions to help you get the best out of your allotted time - does my child try hard enough, is he happy at school, has she made friends? - pretty major queries to settle in around 300 seconds.
Worldly-wise parents suggest you pin down teachers and insist on a results prediction. "It's no use thinking he's heading for a level 4 in national tests when a 'he'll do OK' actually means a 3," says one.
Opportunities for feedback should be more frequent, more informative, and less intimidating. One idea is a priority system over three evenings with children categorised by the importance of seeing their parents, but that would rely on teachers giving up more time and the unions have strong views on this.
A more radical suggestion is a complete timetable change - lengthening the school day (on the continental model) to leave one afternoon free for staff meetings and parental time. Fine, but a headache for working parents.
In an employment situation, annual appraisals allow anything up to two hours to discuss progress and targets. Children spend at least 1,200 hours a year in school. Is 10 minutes really long enough to ensure they are getting the best out of it?
Annie Ashworth is co-author of Trade Secrets: Parenting (Orion, pound;20)