I've used vintage machines for most of the last 30 years, but a year ago my friend gave me a modern Bernina, I used it hard for the last year and now it has an issue and needs a trip to the shop so I've switched to my back-up/class machine.
How I miss my knee lift! And my friend who gave me the machine never used it.
The other thing is the bobbin sensor. It never was that big a deal before, but now that I'm used to the sensor I run out of bobbin thread all the time, usually I don't figure it out until at least a foot or two of sewing has gone on that didn't go on...