In theory it is up to you whether you want to work primarily in terms of magnetic or true headings/ bearings/ courses. Obviously if your choice is mismatched to the readout of the instrument you are looking at at a given instant, then you will have to make a mental correction, which can be either merely inconvenient, or disastrous, depending both on the particular situation, and on your competence at such things. Since there is no way to make a standard aviation magnetic compass give a readout of a true heading, the normal aviation practice, and arguably the best aviation practice, is to work entirely in terms of magnetic headings and bearings. Runway headings and AWOS/ ATIS wind direction annunciations and airway bearings on sectional charts and headings for instrument approaches are all labelled accordingly. Perhaps at some point in our ever-more-computerized future, this practice will be seen as quaint and antiquated. Setting your directional gyro (if present) to true rather than magnetic heading is always an option if you aren't afraid of the math in comparing to the wet magnetic compass, and if for some reason that's what floats your boat, and if you aren't shooting instrument approaches and landings or talking to ATC.
If you are flying in daylight over a man-made landscape resembling a north-south east-west checkerboard as can be found over much of the central US, and you aren't going to be flying in or above clouds for extended periods or giving headings to ATC or recieving headings from ATC or shooting instrument approaches, there is a significant case to be made for setting your directional gyro to the true rather than magnetic reference frame. But in such a case you could do almost as well to just "eyeball" your course without ever looking at either the magnetic compass or directuonal gyro. When it really starts to matter, in most cases you'll be best off to follow the standard aviation practice and work exclusively in the magnetic reference frame, unless you are flying with computerized displays that can do all the relevant conversions for you at the press of a button, and your contact with ATC is minimal.