Two types of operational parameters are used in a particle beam microscope. First parameters influence the image quality, and have settings that are alterable by a user in view of obtaining a better image quality. Second parameters characterize the mode of operation, and the image quality becomes poorer when these change. A mode of operation of the particle beam microscope includes: registering of settings of the first parameters and the second parameters, which the user undertakes in a period of time; analysing a plurality of recorded settings of the first parameters and of the second parameters; determining settings of the first parameters which are advantageous in view of the image quality on the basis of the current settings of the second parameters; and setting the determined advantageous settings of the first parameters.