If you have friends who are openly talking about killing themselves, you can probably relax. I don't think that people who talk about suicide are likely to follow through. No, generally it comes out of nowhere from an outside point of view. Like Anthony Bourdain. He was a guy who seemed to have it all under control. Plenty of money; well respected; great job; plenty of friends. Everything to live for! Then, suddenly, he hangs himself in a fucking hotel room. You may think, “wow, I never even knew he was depressed,” or you may think, “no surprise, really, his mood always was a bit dark.” But if someone is bringing up the possibility in casual conversation, you probably don't need to notify the authorities.
There are many categories of people who are not serious about suicide. These include, but are not limited to: people who announce the intention without forming the intention; people who “attempt” suicide; people who are hung up on choosing a methodology; people who are planning an ideal suicide; people who are wondering if it “hurts” to wrap your head with a dry-cleaning bag; people who are wondering “how long it takes to drown;” people who still think that suicides might go to hell; and many others.
People who are serious just do it. Quite a while ago, the sister of a friend of mine killed herself. She had a failed attempt with pills, and she ended up in a locked room in a nice crazy house. The first chance she got, she knocked out one of the cleaning staff, let herself into the maintenance closet, bared the door, and wrapped a garbage bag around her head. She got her wish; dead as a door-nail before they found her and broke in. She was serious.
One lesson here is that pills very often lead to a mere “attempted suicide.” You'd do better with a good, solid plan. Nobody wants to end up sitting in a wheelchair drooling into a cup. Jumps from high places, and even self-inflicted gunshots, can also leave you alive and miserable.
What's the rush anyway? It comes for us all in its own good time.