Singletary: Sharing a getaway? Then also share your financial ground rules

YOU'RE BACK FROM your summer getaway - but you're steaming that your fun in the sun was more like a blistering lesson in the financial vexations of vacation sharing.

Or maybe your vacation home has become more like a hotel, with people inviting themselves for an extended stay - only they don't expect to pay.

You may love them, but family or friend vacation freeloaders can be frustrating. Yet you understand and even sympathize with their motivation. Vacations typically aren't cheap.

The average American household planned to spend $1,798 to take a summer trip, up about 11 percent from last year's average of $1,621, according to Allianz Travel Insurance. The company estimated that travelers would be spending $89.9 billion on summer vacations this year.

And once people are away, they often part with more money than they had planned. Experian Consumer Services found in a survey last year that 68 percent of travelers overshot their budget, often putting the extra expenses on a credit card.

I asked readers to tell me about their vacation-sharing annoyances.

Kathleen had to fork over a $150 fee when guests didn't properly clean their side of a timeshare villa.

"The other family simply didn't do anything, and apparently left a big mess," she wrote. "When we brought it up, they said they thought it was like a hotel. We made sure they had a copy of the checkout rules. We have never vacationed with this family again. We didn't ask for any money toward the timeshare, as it would have cost the same with one family or two families staying. We shared food costs just fine. I just never understood why they thought it was OK for us to clean up their mess when we were both on vacation."

Karen and her husband purchased a sprawling vacation home with five bedrooms and three bathrooms on a river in central Wisconsin. For the most part, guests are generous with helping out, she wrote.

"Unfortunately, a few of our closest friends are the worst guests," she wrote, "not lifting a finger to help during the weekend events. They wait for us to mix them a drink or serve their breakfast. Maid or butler service does not come with the invite! And in the bunch are messy people who pay little respect to our home and toys."

Here are some things to determine up front if you're going to allow folks to vacation with you or use your vacation home.

Talk about the money.

Be very clear about all costs. What you will cover? What they should cover? Set up a formal meeting to discuss financial expectations before any travel arrangements are made.

Let's take jointly vacationing at a timeshare, for example. When you check in, have the family staying with you also put up a credit card. If they are in a separate villa, even if it's in your name, do the same thing. As the vacation comes to the end, get the bill the day before checkout and divvy up any charges. Let them know, as you speak to front-desk personnel, that any charges for extra cleaning or breakage incurred where they stayed will be put on their card.

If it's your vacation home, establish some written rules. Send potential guests the rules before you agree to have them stay. They break something, they pay for it. Manage expectations that you'll be their driver and tour guide. Hand the guests the rules again upon arrival and post them.

"What I would like to impress upon guests is to pay attention to the needs of the owners," Karen wrote. "If you see [the owners] going through alcohol, food supplies, boat gas, etc., find the means to pay them back. We enjoy having our friends visit, but after the expense and work of the last few years, we have limited our invites and are starting to appreciate a life of solitude."

Include in your discussion the way you vacation.

I don't like to cram in a lot of excursions on my trips, no matter how exotic the location. I vacation to sightsee but also to just chill.

But perhaps your traveling companions want to see every sight possible. Let them go - on their own dime and time. You shouldn't feel obligated to spend like they do - or for them - in the spirit of vacation unity.

Vacation sharing can be a great way to bond and share expenses. But if you don't have candid conversations before your bags are packed, you'll drag back emotional baggage of a spoiled summer trip.