It really depends on what you need. I spend a lot of time in the promotion threads after each new installment goes live because I'm trying to turn on the monetization, and that requires the story to have 100 subs. So, the sub-for-sub economy is really helpful when you're just building your audience and groundwork.
(Just for background, I'm trying to rebuild my fiction career. Due to agent problems at the time, I got caught on the wrong side of what I call the "Lord of the Rings glut" - that time around 2001-2003 when the fantasy publishers bought every remotely Tolkien-ish book they could get their hands on, creating a backlog that extended response times from months to years - and that left me with a single e-book before that medium had come into its own, and forced me to concentrate on non-fiction. So, I'm trying to rebuild a readership from the ground up.)
But, that's not all I'm doing promotion-wise. I also post on my Mastodon account (as a mental abuse survivor, Twitter would be a REALLY bad place for me) and on Reddit (I lost access to my Facebook page due to forgetting to update my cell phone number in the account information after changing it and getting screwed over by the two-factor authentication and Facebook's black box nature...to this day, they won't sent me the email to verify who I am, no matter how many times I ask them to). I sent review copies of Re:Apotheosis out, and while I didn't get very far with them, I did get one external review, and that's useful. And, I participate in these forum threads and the Discord, making sure to post the link to my series when I can in the threads. My quick guides are also used to promote my series (which is very meta, so other writers are the sort of people who would probably enjoy it).
The conventional wisdom that I remember hearing is that somebody will look a new book or product 3-5 times before committing. So, it really is matter of getting eyeballs on your story. It doesn't matter to me if I have to post the link to a chapter 30 times in various places - if a couple of people become regular readers, and they go and tell one other person, that's a victory.
I'm hoping that once I've got enough eyeballs hitting the chapters on a regular basis that I can launch a Patreon as well, but I need to build up the numbers first...and, as far as I know, that's a slow game.