As you get older, there is the tendency to start sentences with, “Back in my day … “

What follows is a blast from the past on how certain things were done. But doing the right thing never gets old.

For example, when you receive a gift or someone does something extraordinary for you, the polite thing to do is send a thank you note. Not a text with a smiling emoji, not an email, but an actual note with your handwriting — however bad or good it is.

During a recent online discussion, I received a comment that necessitates revisiting a column that generated quite a bit of condemnation from millennials who thought I was out of touch with how young people roll today.

In the column, I put out a passionate plea for people to stop charging me to attend their celebrations — such as a birthday or anniversary party or the impending birth of a child. I included the hashtag #guestsdontpay.

“I remember that column, and my reaction to it was ‘that’s not how life as a young person works,’” the reader wrote. “I’m in my mid-30s now, and still when my friend group arranges to go out for someone’s birthday, promotion, etc., it’s normal and expected that each person pays their own way. No one I know can foot the bill for an entire group’s restaurant and bar tab. If we all stuck to the ‘you invite, you pay’ rule, we’d never have any celebrations that didn’t involve the host cooking, cleaning, and otherwise handling all the preparation.”

Let me be clear before you post a comment that I don’t understand the financial constraint millennials face, which I do. I’m not talking about casual gatherings in which friends or family members decide to meet at a restaurant to celebrate something. In this case, the expectation is that you pay your own way.

I specifically mean that if you send an invitation asking people to attend your fill-in-the-blank occasion, you are therefore the host of said celebration. And as host, the expectation is that the folks you are inviting do not pay for the privilege of being in your presence.

If you have a dinner party at your home, you wouldn’t hand the guests a bill for the groceries. Nor should they expect to chip in for the chips and dip. (Having a potluck dinner is totally different).

So much of personal-finance advice centers on paying off debt or saving for an emergency or retirement. You only have so much money, and it’s important that you figure out how to make it stretch. One way to do that is to avoid being trapped into situations in which you are forced to cough up money you really can’t spare.

Or maybe you have the cash but would rather put it toward your own financial goals.

Asking guests to pitch in for the party can put them in an awkward financial position if they weren’t aware of this new etiquette.

But I really want to address these sentiments in the reader’s statement:

• “No one I know can foot the bill for an entire group’s restaurant and bar tab.”

• “If we all stuck to the ‘you invite, you pay’ rule, we’d never have any celebrations.”

Is it really the rule now that it’s OK to shift the financial burden of your desired celebration to your equally financially challenged guests?

This custom now of splitting the cost of the party — without, or even with, the knowledge of the partygoers — is an example of having an entitled mentality.

It is also a false narrative to tell yourself you can’t truly celebrate unless you go out to a restaurant for your milestone event.

Yes, turning 21 or 30 is a momentous occasion. But if you’re still struggling to pay down student loans along with your friends, host something at home. The atmosphere with pizza can still be festive. It’s about the people, not the party place.

Or, given your financial situation, you have to be OK with your special day coming and going without a group gathering. There are things you won’t be able to do because you don’t have the money.

I know that over time social norms change. Still, young or old, you are not entitled to a restaurant bash with your friends if you don’t have the cash to treat them like guests ought to be treated.

This is about living within your means. And, yes, this may mean living with celebration limitations.

— Washington Post Writers Group