[dyselon]

Is there a good reference for potential upgrades to old, obsolete-ish parts? I definitely understand that many of the old logic ICs, transistors, and op-amps have been displaced by better parts, but I don't always know how to identify them short of a parametric search on digikey and hoping there's not some sharp corner I missed. I'd find a lot of value in a page that had some recommendations for "Are you using <OLD PART> for <PURPOSE>? Consider <NEW PART>!"

[CamperBob2]

Not really, because as so many commenters have pointed out, the choice to use "antique" parts is more of a value judgement than a violation of natural law.

When in doubt, your best move is probably to see what Horowitz and Hill have to say. AoE3 has a lot of specific component recommendations.