After doing the horribly restrictive diets that are so time-consuming what I found works best it what you had mentioned. I eat low carbs which I found is quite good for my weight control too. Overall I am pretty lucky, compared to a lot of people. I have 2 or 3 breakouts a year and eat what I want most of the time although I try advoid carbs when I can. Although it seems for me my symptoms have changed. I used to get chronic yeast infections and now instead of one large breakout I get symptoms like itchy ears and itching on my skin that I just can't seem to get at. I guess little symptoms are better that a full yeast infection.
I want to believe that things are getting better but like you had mentioned you can be symptom free for a long period of time and then have a breakout again. And this will sound corny but what I has helped me the most is basically to NOT focus on yeast anymore. I meditate daily and I reaffirm how healthy I am and how good I feel. It seems like the more I focus on how I want to feel the more I feel that way.