In article ,
Mxsmanic wrote:

Do you have a marked "zero point" for the trim, or do you just trim
until it feels right for the circumstances, and then trim again the
next time as required, without worrying about whether the trim is
truly "zero" or not?

There are marks/indicators, however they are mechanical pointers which
are subject to deviation. In actuallity, yes, you move the trim control
until the pressure is neutralized (in the case of elevator for the the
speed and power setting, and for rudder until the yaw ball is centered).