Should you really tip your Uber driver? The answer is becoming a lot more clear.

The ride-sharing company recently announced that it will give riders the option to tip from the Uber app after every trip. Lyft, one of Uber's competitors, already has a similar tipping feature.

As a general rule of thumb, etiquette expert Diane Gottsman suggests leaving 10% to 20% of the fare.

Etiquette expert reveals how much to tip

Uber and Lyft drivers are often forgotten when it comes to tipping, but they’re not alone. Many people don’t realize that pizza “delivery surcharges” don’t typically go to the driver.

Here are some other tipping guidelines from Gottsman, author of the new book "Modern Etiquette for a Better Life."

Food delivery driver: 15% to 20% of the bill

Flower or cookie delivery: $3 to $5 per delivery

Tip jars, such as the ones at coffee shops: Not mandatory, but you can leave loose change or $1

Uber or Lyft driver: 10% to 20% of fare

Hotel housekeeper: Tip $2 to $3 daily; $1 per guest after five people

When in doubt, do a Google search using your smartphone for on-the-go advice. You may also want to ask a friend or family member who is a tipped employee for their perspective.