Postfix will run forever, but other hosts won't accept your emails forever unless you keep up with the latest spam techniques (DANE nowadays, isn't it?)
Personally, I just use a free smarthost, but that loses some of the privacy advantages.
Personally, I just use a free smarthost, but that loses some of the privacy advantages.
For myself I am going with a major commercial antispam solution, which is hosted in two of our datacenters. Since I am working with the developers and admins on regular basis there's no reason not to trust them.