This is good advice.
There's been a lot of statements about adding co-authors to papers.
A paper is not a patent, you can add whoever you want. A good rule is whether their intellectual contribution helped the paper. (Thread). https://twitter.com/TrevorABranch/status/1296886944253714432

If it didn't, and you will remove name from co-author list, then scrub that person's contributions from the paper.
Paper not sufficient?
OK then that person was important. Add back in.
Or, if person did not contribute intellectually, but did work, then put in acknowledgements.

If person performed a function or task that was clearly spelled out, then that's not an intellectual contribution.
(If you sent samples out to a pay analytical service laboratory with a menu check-list, would you list all the people who processed your sample? No.)

But if during the course of the work, the person makes an inventive step, "ya know, here's a new thing I discovered in the data" or "here's a new better way of doing this".
A key is if the contribution is better than the state-of-the-art (what is already in literature).

A key is that a scientific paper IS NOT a legal document. You can put whoever on you want. The worst you can do is hurt feelings. (Avoid this, tho.)
However, a patent is a legal document. The rules there are much more strict.

For a patent, if someone wasn't on there that was part of the claim - the patent could be ruled later to be invalid.
If someone was on a patent who did not make an intellectual contribution ("oh we always put the Director on to help his CV"), you could invalidate the patent.

For a patent, I used to have the uncomfortable conversation where we laid out the claims, then details of who, and exact how each person contributed. Super-detailed. If claim modified or dropped, person's name could be dropped depending if that contribution is claimed.

Patents are not popularity contests. They are defensive. They WILL be attacked in court. Need to be ironclad and buttressed.
Inventorship is a really big deal. Need to state how contribution went above state of the art AND not obvious to someone skilled in the state-of-the-art.

So reading up on literature and performing work that is current state of the art is not inventorship. Not enough for a patent, judgement call if good enough for co-authorship on scientific paper. (Scientific papers not legal documents.)

For a scientific poster or presentation that is providing an update on research progress (which will not be directly subject to later peer-review)? Oh heck yeah, pile on the co-authors!
The bad thing on this is the painful abstract submission forms you need to fill out.

For me personally when deciding coauthors, I try to start with using inventorship definition from past patent work, then relax a little bit. Some journals require a statement describing what each co-author contributed, but it's usually pretty relaxed and not rigorously detailed.

And I once (very long ago in another field) had an issue where I saw a manuscript that had my own work, but I wasn't on the co-author list I confronted the lead author.
"You didn't do enough work to justify your name on the paper".
OK. Remove my work then. This diagram here..

...this paragraph here. These table entrirs. These sentences in the conclusions. And this section of the Experimental.
"But that will weaken the paper!" said the author.
Bingo.