With Thanksgiving and Christmas coming up I would like to ask whether the standard tip amount in United States restaurants needs to be increased on these days.

Please note "needs" means "it is expected," not merely "it would be gracious."

I am sure it would be gracious, but that is not what I wish to ask.

Also: I heard some restaurants have prix fixe and/or auto-gratuity on these days. If auto-gratuity is included, is a further tip needed? (I saw a post somewhere from a self-professed ex-waiter that said yes, but that struck me as ridiculous--but maybe I am off base.)

I tip in relation to the quality of the service, not based on the calendar.

If a mandatory gratuity is on the bill, I see no reason to tip more than that unless the service was outstanding.

I have yet to see a mandatory tip, except in the case of parties greater than six typically. Barring a mandatory tip, I know of no instance where the percentage is up to anyone but the person paying it.

I give a special "gift" to the staff at my regular joints around Christmas time (east side of Pacific) and Lunar New Year (Far East)

If they have a mandatory gratuity you don't need to tip on top.

If they don't, you don't have to tip more, but the high end of normal (20%) would be appropriate.

Check the bill at the end.

A mandatory gratuity kind of nullifies the definition of the word

Like a poster above mentioned, I will leave a larger tip for the staff at my regular spot and wish them a happy holidays so they know why the gratuity would be a big bigger than normal.
This is a special one off and would not consider anywhere else. When I walk in the staff greet me and my better half by name, we engage with them on a personal level and know many of their stories as they do ours.
Sadly places like this don't last forever in my city and there is a rezoning application for their building and adjoining building. Likely to turn in to a condo soon. Good people will be without work and I will be without a friendly local.

I agree, this is the ONLY reason to increase the tip during the holidays, unless you're a reformed Scrooge. It is certainly not an expectation.

And as others have said, if the tip is included on the bill, no need to add to it. That's so uncommon in the US (except at high end restaurants using a ticketing system), that they can't possibly expect anyone to tip on top. And to the OP, in my experience waiter and waitress friends will tell you all day long how hard they work and that they deserve way more than a 20% tip...it's actually quite annoying, but shouldn't change your behavior at all.

[QUOTE=JBord;29116040 in my experience waiter and waitress friends will tell you all day long how hard they work and that they deserve way more than a 20% tip...[/QUOTE]

This has not been my experience at all. Ever. Every single server I've known, and there have been many, have said they would be ecstatic to receive an average 20% tip. Bartenders not included.

Maybe it's a Chicago thing, but a couple industry people I know say 25% (which is annoying when I go to dinner with them), and that's what they tip. If I don't go along, they'll make up the difference, which of course means I'll just go along. I'm usually an ~18% guy, so not like the extra makes a huge difference, it's more the principle.

There is no need or requirement to tip more at the holidays. It's up to you.

On the second question, it's becoming more common for restaurants to have no-tip policies (and thus tip-inclusive prices). I've dined at several in the past year. Most didn't even offer a tip line on the credit card slip. But they also will almost certainly tell you: "The tip is included in the price," and they are almost entirely rather high-end, high-priced places to begin with.

I tend to tip pretty well in general, but I always step it up around the holidays. Adding an extra $10 or $20 on top of a 20% tip doesn�t hurt me in the long term, but it improves the day of ppl working on the holidays. I have a good career these days, but I spent a lot of time in the hospitality business in a previous life.

I err on the side of being generous and pleasant, and it has served me well, imho.

Interesting how you say being generous "has served me well" - have you considered what happens after you leave that restaurant?

The customer who has that server after you and leaves a 20% tip, which is high standard these days, may leave behind a negative impression on the server, which may carry over in their work. The sad fact is that one extravagant gesture sets an expectation of how future customers will tip for same service. I'd rather see a restaurant pay reasonable compensation, be it time and half or whatever the industry norm might be, for holidays, than have an expectation that customers will significantly increase tips because of the holiday because not every customer can or will throw in that extra $10 or $20.

Corresponding with that, has anybody else noticed how holiday menus are often pricier than for the same dishes on non-holidays?

Here it's all about expensively priced holiday set menus in Korea. Restaurants and hotels treat it like a second Valentine's Day.

Absolutely on Valentines Day. Can't remember noticing it on other holidays.(in the US)