I am going to be honest in that I am a little confused by your question, but I am going to answer for what I think you are asking...
As for how long rejection would take to show up - it varies. Many patients experience at least 1 bout of rejection in the first few months post transplant. For me my first issue with rejection came at my 2 years post transplant appointment. Even at that I had no symptoms it just showed up in a bronch.
As for how long it takes for rejection to destroy your lungs post transplant it depends on what you are dealing with rejection wise. Acute rejection can hit unexpectedly and take your lung function down relatively fast but it is normally treated and you go on with things. Then you can have instances like I did where you have acute rejection but it is so acute that you never experience any setbacks. Chronic rejection I think is more what you are talking about though. That is a prolonged issue that involves more dealing with prolonged treatment to manage the effects of rejection. It depends on the aggressiveness of the rejection and your immune system. I know and have seen some people go down in a matter of weeks or months and I have seen some people change meds and get more aggressive treatment and it sustains them for years despite the chronic rejection.
I don't think that any doctor can really say right off how long you have when it comes to Chronic rejection I have seen them tell friends that with the rejection they are dealing with they would have about 12 months only to see my friend on a vent within 2 months and vice versa. So like I said there really is no way to tell.
As for how long you have to be transplanted again. I believe, but I may be wrong, that decision is more based on health and compliance with prior treatment. I know of people that were transplanted 10 years after their first transplant due to rejection and some are relisted within a year. More goes into it than just how long it has been since your last transplant. I do believe it is a more involved process the farther out from transplant that you are, but I don't think that alone would prevent you from being relisted.
The people that I know that have had to be relisted most of them are with no problems. There have been a few that were denied but for varying reasons - none of which include time post first transplant. One was denied because of failure to comply with prior treatment plans set by the docs. One was denied because he had massive organ failure and though he survived they were never able to determine what the cause was and to add to it he had problems with his diaphragm and they were afraid he could be on a vent for the rest of his life even if they re transplanted him. The other also involved health issues that made the risks to the docs appear to great - there was a slim possibility the person would have come out fine but most likely they would have passed from the other health issues they were fighting when the stress of the transplant was added to the equation.
I don't know if that answered your question at all, but I hope it gave you some useful information if nothing else.
The best thing to do if you are post transplant and having issues is to talk to your team. If you are pre transplant and just curious - then talk to your team. Your transplant team will be able to give you more exact information on their protocols and the way that they practice when it comes to the rejection issues. What I mentioned above was simply based on my center and the way that they manage whether or not they relist people.
Lindsey