LET'S BE HONEST: parents thinking of hosting foreign students for the summer are thinking first and foremost about money. They will earn £75 per week per student - and most take two - for most of the summer months, providing food and board and some entertainment in exchange.

And if their own children complain, parents may not be sympathetic. "Go on," said one mother, "stop whingeing and take your school fees out for a walk."

Most parents would share her pragmatism, but many would also say that summer students, usually aged from 12 to 20, have enriched their family's life. For many suburban children, the students have always been just a fact of life.

Eoin O'Brien, chairman of the Recognised English Language Schools Association (RELSA), reckons that during the years he accommodated students, his children probably did resent their intrusion a little. "But it wasn't a democracy, it was just a question of `the students are coming'.

"Maybe now they'd tell me it was traumatic beyond belief, but it wasn't a question of abject discomfort, just having to share a bed with another child. It's all part and parcel of the rough and tumble of family life."

Your children may grumble at having to bunk in with brothers and sisters, and feel shy about including visiting students in their activities. But many parents do expect their children to make an effort, and it's probably good to encourage them to do so, says Susan, who has been hosting students for over 10 years.

"My three kids aren't shy now with strangers of any nationality. The youngest, who was only three when I started, can mix in with anybody, and the eldest wasn't at all worried about going to France on an exchange last summer.

She also forced the family to do things she's sure they wouldn't have done otherwise: "They know art galleries and museums backwards."

On the other hand, she has stopped taking students the same age as her own children (now all teenagers) and now specialises in providing accommodation for adults. "Your kids do get fed up. Mine don't mind having to give up their beds, but I began to feel it was unfair that their summers should revolve around entertaining their students - because I did expect them to take the students out with them."

It was very important to make it clear to her children that, for her, they were "number one", Susan says more important than visiting students. She also made it clear to recalcitrant foreigners that they had to make an effort too.

"Most students are fine. But sometimes you'll get a personality clash, or a child who comes expecting to be entertained, or who won't respond to your children's efforts to involve them.

"I'd take them aside and tell them: my kids are human too. If you don't respond, they won't go on asking you. And if it didn't work, I'd tell my kids: okay, you've done your bit."

Eoin O'Brien advises anyone who is thinking of joining the 50,000 to 60,000 Irish families who host summer students annually to think about these things, because each family will have different attitudes. Parents shouldn't put pressure on their children to be friends with their student, he says.

"Our schools don't promise friendship to overseas students, because you can't assume that two 14 year olds, for example, will get on. If it happens, it happens." (O'Brien admits, however, that he used to tell his own children, "For God's sake, bring them out" - and within reason, they would do so.)

SOMETIMES visiting students just don't fit in. You hear horror stories from both sides students made to eat by themselves, or a visitor who is sullen, uncooperative and demanding. If things don't go right, they can put a tremendous strain on everyone. What to do?

Act fast, say the experts. Anyone who has been in this kind of situation knows that letting it fester will not make it any better, and sometimes you have to be cruel to be kind.

"If there's bad chemistry, most organisations will switch kids," O'Brien says, highlighting the importance of checking if the school providing your students is in RELSA, a body recognised by the Department of Education.

If a school has organised things properly - vetted their host families, briefed everyone properly - things should work out. "We get a lot of repeat students, and 99 per cent like their families," says John Carlos, who runs the International Summer School in St Michael's College, Dublin, every summer. "If the families are right, everything is right."

The are 120 or so families on his books. The mother in one of them explains: "What they're really looking for is generosity of spirit, for families who'll be polite to students and include them in family life. And if your own children are going on foreign exchanges, you really appreciate how important this is."

Ireland, which attracts about 150,000 students a year, has a good reputation as a place where families are hospitable to foreigners. So if you think your children will wear it - and that you can stand all the housework - it's probably worth considering.