Anecdotally I worked as a part-time volunteer on a general counselling service for a couple of years in my twenties - which included some suicide calls. A goodly chunk of the time it felt like you made a difference. We occasionally got "thank you" calls weeks/months later to say that we'd stopped folk doing things that they would now regret (sometimes from folk you thought you hadn't helped...)
Anecdotally I worked as a part-time volunteer on a general counselling service for a couple of years in my twenties - which included some suicide calls. A goodly chunk of the time it felt like you made a difference. We occasionally got "thank you" calls weeks/months later to say that we'd stopped folk doing things that they would now regret (sometimes from folk you thought you hadn't helped...)