I haven't had a bronch either (knock wood), although I've had lots of offers. I first got sick when I was 21 after a bout of pneumonia that never went away.
About a year later, they found pseudomonas and I went into the hospital for IV treatments. When the doctor said he wanted to do a bronch, I asked, Why? Is it absolutely necessary? Would you change my treatment?" He said, "No, but it might give us a name for your disease."
They suspected adult CF. I had pseudomonas which was being treated-- so to have a bronch to label the disease -- not a good enough reason.
Another time I was in the hospital (pseudomonas again) a different doctor wanted to go in and suck out the mucus. I said, "But I'm coughing it out without a problem. And I'm getting better." Again. No thanks.
That same doctor offered a bronch again when I was really sick with pseudomonas and hemoptysis. I asked if I could wait a day and see if the IV antibiotics would stop the bleeding and it did stop.
I've had others suggest bronchs too. I asked my present doctor whom I trust, if it would have been a good idea for me to have had a broch. She said, absolutely not. She said she prefers less invasive ways of opening the airways and getting the mucous out. As far as diagnosis, CT scans really give a lot of information. Although you don't want them too often either.
For me, the biggest negative is there is always the possibility of introducing new bacteria from improperly sterilized equipment. Not to mention there are doctors who make a lot of money doing bronchs all the time. And if the culture shows what the bugs are and you respond to your treatments-- what's the point?
I am not saying that bronchs are never necessary. There may be other reasons other than what I've mentioned for their use. I can only say that for me the question always was and is to anything invasive or possible harmful, "Is it absolutely necessary? And will it change how you are going to treat me and how?
You asked a simple question and I gave a way too long answer.