As a nation, we’re pretty much used to tipping the wait staff at sit-down restaurants based on the price of the meal, but for most of us, deciding when to tip for personal services in other situations is a conundrum.

With companies trying to earn your business by providing new, personal services, questionable tipping situations arise all the time.

For example, Avis provides free pick-up and delivery within five miles of its neighborhood locations for customers who need a ride to the Avis office to pick up a rental car.

Should the driver who picks you up be tipped?

For people who opine about etiquette, this question seems to be flying under the radar, so perhaps we can take etiquette guidance from other situations that involve baggage handling.

For taxis and limo drivers, as well as courtesy shuttle drivers at airports, the lowest tip seems to be $1 per bag if the driver doesn’t help load them or $2 per bag if the driver helps.

Many etiquette pundits recommend keeping a stash of $1 bills so you’ll be ready to tip service providers when you travel.

As for when to tip, do it when you arrive at the destination.

But only tip if you feel you’ve been given satisfactory service.

I will always remember wedging my unbelievably huge hard-sided suitcase in the extremely narrow stairway that led to my “room” on an Amtrak sleeper car.

Before attempting the stairway, I had looked plaintively at the porter, who was completely unresponsive. Needless to say, that porter did not rush to my assistance as I struggled to free my suitcase, and, as the service never improved through the rest of my trip, I’m sure everyone went tipless from me.