“Destination weddings” can be fun. And time-consuming. And terribly expensive. Those most likely to be invited to a lot of weddings — people in their 20s, say — also tend to have the least seniority at work and the least disposable income.

So what’s a modern wedding guest to do? A primer:

• Do you have to attend?

“People who are having a destination wedding absolutely expect certain people can’t attend the wedding for financial or schedule reasons,” says Carley Roney, co-founder of the wedding planning Web site TheKnot.com. But she advises against mentioning your finances when you decline. “It’s such a guilt-tripping kind of thing,” she says. “Come up with a very appropriate reason, even if it has to be a white lie.”

• Must you stay where the bride and groom suggest?

The couple will likely offer information on a range of accommodations, and they may have blocked rooms.

“In a situation where the bride and groom have not been so thoughtful,” says etiquette expert Samantha von Sperling, founder and director of Polished Social Image Consultants in New York, “go online and book your own accommodations, and then you can call them and say, ‘I’m sorry, but I couldn’t afford the place you picked, so I’ve found something else just down the road. But I promise I’ll be there and be on time.”‘

• Do you have to attend every planned event?

Destination weddings often involve a raft of events, including a cocktail party to welcome guests and a brunch the morning after the ceremony. If three solid days of bonding with relatives, co-workers or strangers doesn’t appeal to you, Roney says it’s fine to opt out of a few daytime events. But if you’re skipping something, let someone in the bridal party know so that no one waits or searches for you.

• What if you’ve got kids?

If children are invited (with destination weddings, they often are), your hosts may have some child care planned. Ask whether kids are welcome at all the weekend’s events, then ask if baby-sitting is available during any that are grown-ups only. If nothing has been arranged, you might contact the hotel and inquire about baby-sitting services.