Having been force-fed the stodgy end of the romantic repertoire at school, I grew up hating it. I've since managed to find my own way into much of it, but there are other areas that are not only impenetrable binge-eating disorder zones (Elgar), but thankfully it's quite fashionable not to like them so I don't have to bother trying
I'm in rehab on Wagner - I seem to remember that in 1991 I didn't listen to anything
except Wagner (except, perhaps, Pfitzner), but these days I can get through entire years without listening to a note of it. But I could so easily be dragged back in again
(Continued post-WW2 wariness of his music in Russia makes a very convenient form of Albericholics Anonymous). I come and go with Puccini, but I think that's mainly due to over-familiarity with his output (some of it work-related). I wouldn't cross the street for another LA BOHEME, I'm afraid, but I would jump on a plane to hear FANCIULLA DEL WEST.
I tend to listen to whatever I'm working on, and whatever adds the background context to it. I've spent the last 3-4 months listening almost entirely to Handel, leavening that with a bit of Porpora, Hasse, Vivaldi etc. Then I have to do the same with Purcell (both anniversaries next year). I think I'll be taking Boulez, Nono, and Birtwistle to listen to on the beach next year, I'll be deeply into da-capo overload by then
Somehow I can always find space to listen to the Ars Nova and Ars Subtilior composers, and Ockeghem & Dufay. It's like having a musical steam-bath that deep-cleans the accumulated goo out of your system