Not the OP, but I've been running my own email server since about the same time-frame (and it started life on a dual CPU Pentium 100Mhz box). Total time invest

Not the OP, but I've been running my own email server since about the same time-frame (and it started life on a dual CPU Pentium 100Mhz box). Total time investment since circa 1998: estimated maybe 100-200 hours total (note, over an approximately 20 year span), and most of that was spent during the inevitable of reinstall new OS on current or newer box, then move config over portions of the process. I've also always been on Postfix, which has always been way more secure than sendmail ever was at the time. And Postfix is also much easier to configure for the basic case of "send/receive email for a personal domain".