To tip or not to tip? We spoke with manners expert Lizzie Post to answer all our questions. Her great-great-grandmother, Emily Post, literally wrote the book on American etiquette in the early 20th century, and you can bet that includes a chapter on tipping. Below is a breakdown of the etiquette of tipping at hotels in the United States, according to industry-accepted standards.

Additional Questions:

What kind of services should you tip a concierge for? If the concierge schedules dinner reservations or scores hard-to-get show tickets for you, then show your appreciation.

What else do I need to know about tipping housekeeping? Larger families, or those staying in a large suite, should tip more, up to $5 per night. When deciding how much to leave, Post says to "consider the amount of work housekeeping has to do."

Does anything change if I'm staying at a B&B instead of a larger or boutique hotel? In that case, it's up to your discretion, but feel free to ask the inn's staff what the tipping standards are. Generally speaking, you should leave a tip if there is hired help to clean the rooms.

Finally, a Few Reminders:

Have plenty of singles on hand; often, there's no way to tip most of the hotel staff with a credit card.

The best thing to do if you're unsure about what to tip? "Just ask what the norm is," Post says.

If you do have a poor interaction with a hotel staff member, tip as you regularly would and then ask to speak with a manager about the negative experience. "It's not going to do any good to lower your tip or give an insulting tip amount," Post advises. "Hold up your end of the bargain and tell the [hotel] why you think it didn't hold up its end of the bargain."