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Guitars have a neck tension rod with an adjustment screw that changes the neck bow. They also have intonation adjustment screws that adjust the location of the tail bridge for each string individually. Then there's still tail bridge string height adjustment.

Neck adjustment needs to be done because seasonal moisture changes can change the bow of the neck. Depends on guitar. This is mostly for proper playing action, so strings don't buzz but aren't too high from the fret board either.

Intonation needs to be changed when you change some other things, like the things mentioned above or string gauge for example. There a tuner is very handy, you can compare the string fretted on the twelvth fret to its harmonic there. The differences are small and hard to hear.

Same things apply for electric basses.

Don't know how things are dealt with on a violin or cello, but the lack of frets certainly makes some of the adjustments unneeded.

With guitar, you only adjust these things when doing maintenance, not in the back room and certainly not on stage.