LOS ANGELES (CBSLA.com) — A local expert says may people get flustered when it comes time to leave gratuity.

If calculating the tip has you stumped then the following advice from Mar Vista-based etiquette expert Jules Hirst may be useful.

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“It’s America, we tip on everything!” Hirst laughed.

But before reaching for your wallet, she says there are standards you should follow.

“Generally, it’s 15 percent. It’s going to be 15 percent for just about everything.”

She says in today’s technology-driven age smart devices make it easier to pay. But they also add in many unnecessary tipping options.

“You can pay now on your cellphone, you can pay now on your iPad, so you really need to be aware who to tip, when to tip and how much to tip,” Hirst said.

Jersey Mike’s Subs, Subway and Chipotle all have a screen that pops up on their touch-screen register that offers tip options. Hirst says it’s all right to hit the “no tip” button and instead leave loose change in the tip jar.

Also, Hirst says there’s no need to tip for curbside pickup or food-to-go.

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So when should you tip? She says it’s customary to tip 15 to 20 percent at full-service restaurants. To figure out the correct amount, use the total of the bill before tax.

There are plenty of apps available for smart phones that calculate the tip for you.

If you pamper yourself with a beauty or spa treatments, Hirst says you must tip for massages, facials, haircuts and hair color.

“Someone who’s been going there for 10 years may give 20 percent. First time there, may give 15 percent, and that’s fine too,” Hirst said.

When it comes to tipping hotel staff, allocate $1 to $2 per piece of luggage that the bellhop transports, $2 to$3 to the valet upon returning the car and $5 to $10 for the concierge depending upon the service.

And don’t forget housekeeping. Hirst says you should tip between $2 and $10 a night and write “housekeeping” on the note so they know it’s for them.

When using a car service such as a taxi or limo, 15 to 20 percent tip is the standard. For Uber and Lift, have a few bucks ready to give your driver.

Hirst says common sense goes a long way: if someone is going out of their way to help you out, tip accordingly.

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