Given there are dozens of service industries where tipping is expected in the U.S., it can be quite the minefield for consumers to navigate.
Most of us will commonly run into tipping situations when eating out. The Tip Jar looked at the etiquette for when and how much to tip for food and drink in this column.
But there remain some burning questions that need answering, so we've dived back into the world of tipping to provide some more guidance.
Do you tip pre- or post-tax?
This question came from a reader, Barb, who noticed that some restaurants have started putting different percentages at the bottom of itemized receipts – some which figure in the tip on the pre-tax amount and others the post-tax.
"I know it's not much difference but what is the correct tip, pre- or post-tax?" she asked. It's a good question and one I hadn't considered before.
I tend to tip post-tax just because it's the number at the bottom of the receipt.
But is it right we do that? After all that's not part of the service the restaurant has provided – it's tax levied by the city/state on your food and drink.
(Here's a breakdown of Minnesota sales tax for dining/drinking, by the way).
What's the verdict?
Sometimes the decision is made for us, with this LA Times piece noting restaurants that feature "suggested gratuities" or tipping options that appear on credit card transactions are often based on the post-tax calculation.
But several tipping etiquette experts and websites suggest you shouldn't tip post-tax at restaurants.
The Emily Post Institute says wait service at sit-down and buffet eateries should be tipped based on the pre-tax total, though the institute seems to think it's OK to tip post-tax on your bar tab.
The Etiquette Scholar website agrees, saying at restaurants you should only tip on the pre-tax amount of the bill, not on the total.
Laura Barclay, an etiquette expert from the Civility Center, told Tip Jar she's also of the opinion that tipping should be calculated pre-tax.
The difference is negligible, coming to as little as $2 on a $100 bill. And if you're happy with your service and want to be generous to a server relying on tips for their livelihood, I'm sure most of us wouldn't begrudge them that.
But if you have a principled stance against post-tax tipping, now you know some etiquette experts have your back.
If you have any money questions you'd like Tip Jar to look into, send them to email@example.com or @AdamUren.