Distorted brake discs

I know that it can happen that the discs can be forgiven but all half-years swapping is too expensive for me just because I get into the irons on the AB. These are original parts of Subaru and I only hear from the friendly (We never had any problems with that before). I also don’t have with my other kfz`s. Does anyone have a tip or good experience with other manufacturers? Thanks already.