I (now) use cables that are machined smooth - the outer layer is machined smooth. I think they're 1.1 mm thick.
In the old days there weren't any liners in the cables and cables weren't thin or machined smooth so you had to lube. I'm amazed at how thick my older shift cables are compared to the newer ones - the old cables were basically as thick as brake cables.
I use White Lightning for cable lube. Incredible. A friend (cyclist, ex-racer, ex-bike mechanic, current high end car mechanic/restorer) uses White Lightning in his classic motorsport restoration shop after he saw its effectiveness in the bike shop.
The last new-everything gear cable install (shifters, Nokon housing, cables, all at once) was on a friend/teammate's bike. When I first clicked the shifter I thought for a moment that he hadn't put the cable in because I didn't feel anything. The rear derailleur literally felt like an electric shifter (when I finally shifted one). The front, fine, it's not because of the force required to shift a front derailleur, but the rear was just incredible.
On my bikes I've reused the liner etc and I rarely change shifters so I haven't done a true new install in a while, many years.
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"...during the Lance years, being fit became the No. 1 thing. Totally the only thing. It’s a big part of what we do, but fitness is not the only thing. There’s skills, there’s tactics … there’s all kinds of stuff..." Tim Johnson