One of the more stressful things about travel -- after flying, of course -- can often be insecurity about tipping.

The confusion surrounding this subject was underscored last year when a Yahoo blog titled "Confessions of a Housekeeper" sparked a discussion about whether and how much to tip a hotel maid. I was surprised to see that tipping the housekeeper was not as standard as I had assumed. And the opinions on whether or not to tip every day and how much varied widely.

To me, tipping the housekeeper is a no-brainer. I usually leave a few dollars, as much as $5 a day, depending on the hotel and the number of times housekeeping checks in.

But I find the whole question of tipping a bit stressful at higher-end hotels, where people are falling over you to open doors, grab your bags and flag your cabs. Even more confusing are those instances where 24-hour butlers are provided to make sure your every need is fulfilled.

I waited tables for years in high school and college, so I have always been sensitive about making sure service workers are tipped properly. But restaurants are easy. We all know 15% is the minimum expected at restaurants, 20% for good service.

There are no set rules, though, for hotels. You don't want to undertip, but you also don't want to be the gauche American throwing money around like it's candy and insulting workers who might be above the tipping chain, or in whose culture tipping is not expected.

What's more, the butler service seems to throw many of the already fuzzy but usual rules right out the window.

One of my first experiences with butler service was at the Highmark Resort in Steamboat Springs, Colo. When my husband and I pulled up, someone parked the car. While he was doing that, someone else took care of stowing our gear. While he was doing that, someone else took us to our room and showed us around.

The stress hit immediately. How much do I tip the butler, and shouldn't we also be tipping the other two guys, even though I wasn't sure who they were?

Fortunately, as my husband pulled out his wallet, the butler politely informed us it was best to just wait until we left and offer one gratuity that would be split among everyone who was on duty during our stay.

What a relief! For the rest of our trip we enjoyed great service, free shuttle rides and help with our skis, without having to worry about keeping wads of ones and fives on hand to throw around at every turn.

Still, it's hard to know if that rule applies at every hotel with butler service, especially in developing countries, where every dollar can be so important to service workers.

My tip stress returned during a recent stay at Las Ventanas al Paraiso in Los Cabos, a Rosewood resort that definitely lives up to the company's high service standards. When we were greeted at the airport, we were immediately informed that service charges were included. And on arrival we were assigned a butler, so we assumed we would follow the Highmark rule and give our assigned butler one gratuity at the end of the stay to share appropriately.

Still, we found it hard to be pampered with such great service without tipping. Butlers brought coffee and muffins in the morning. Someone else prepared a fire for us at night. Housekeepers were so thorough they left eyeglass cleaner next to my reading glasses and book.

At the pool, there were attendants everywhere, moving chairs, setting them up with fresh towels and pillows, delivering bottles of cold water and Evian face spritzers at regular intervals.

Though the resort had made it clear service was included, we noticed many of the other guests were throwing dollars around every time a pool boy stopped.

"Maybe we should be tipping everyone now instead of at the end," I said.

"Yeah," my husband joked, "but then they need to install an ATM in our room."

So began the round of insecurity every time someone helped us. Sometimes we tipped. Sometimes we didn't. And in the end, we left a nice gratuity for the butler, hoping he would share it with the many people who had made our stay so great. Still, the questions linger: Did the pool boys think we were stingy Americans? Did we leave too much for the butler? Not enough?

Figuring that I can't be the only traveler who stresses over this question, I decided to consult Lisa Mirza Grotts, author of "A Traveler's Passport to Etiquette."

Grotts says the answer is simple: "Whenever a service is performed of any kind, we need to tip."

"You have got to have your dollars, your fives ready to go," she said, advising travelers to break a 20 or two at the front desk when they check in.

"When you pull in front of the hotel and the guy takes your bags, that's the first thing I do is give $1 to $2 a bag," she said. "Let's be clear. I don't think it's required for someone opening the door for you and smiling, but every time they get your car, anytime someone helps, you need to tip. That's part of the cost of travel."

Grotts said the tipping-per-bag rule applies both to the bellman who takes the bag from your car to the front desk and to whoever brings your bags to the room. If that person also shows you around the room, she ups the tip to $5 or $10.

She said she tips the housekeeper in advance to ensure the best service.

And anytime someone brings something to your room -- the missing hair dryer, etc. -- have a few bucks handy.

The same rule applies if you have a butler. Grotts said that butler or no, she still tips whoever delivers a service.

Still unsure? Ask at the front desk or question the concierge, she said, particularly if they have a policy like Las Ventanas'.

"Traveling should not be stressful," she said.

Indeed, while Las Ventanas has a service charge included, managing director Lionel Alvarez said, "We do recommend also at the end of the stay to do one tip that we distribute internally.

"And we always request the guests do a little note with it, as our teams are very thrilled to read the words our dear guests are writing, especially when their names are mentioned. This, with whatever the amount is, makes a great impact."

Great. So now I'm stressing over whether I should have left that tip at the front desk.

Email Jeri Clausing at jclausing@travelweekly.com.