[nothrabannosir]

Personal experience from mid 2000s to early 2010s. I lost too many outbound emails to the void. Not even spam or bounced; just genuinely gone. Gmail was the only honest receiver, Hotmail and yahoo were particularly egregious. Obviously set up everything: dkim, spf, constant ip blocklist monitoring, etc etc. It got so bad that I started sending follow ups from a Gmail address to ask if they received my email. That’s when I stopped and never tried again.

[sam_lowry_]

I self-hosted for 25 years. My SMTP server is at Hetzner for the last 15 years.

I was probably lucky, but I rarely had delivery problems. The last one was a couple years ago with Microsoft swallowing my emails and it was due to the combination of a fairly old exim and a TLS certificate verification quirk at *.protection.outlook.com. I found a fix in the form of a configuration option somewhere on SO.

I must admit that when I send a really important email, I check the mail server log if it went off without errors, but this does not bother me as checking logs manually once in a while is a good thing anyway.

[yndoendo]

That time period was during my IT consultant days.

We were installing on site Windows Small Business server for them. Issues were rare and one offs with self hosted email. The only issue of delayed messages was during changing IP addresses and DNS records, waiting for the updates to replicate to root servers.

Companies would often have a server just for email hosting running Linux on low power hardware. [0]

[0] https://en.wikipedia.org/wiki/Cobalt_Qube