Best wishes. You're grappling with one of the most challenging "what ifs" we have to confront on the path to donation. Donate now, when qualified to donate, to someone in definite need, now, or hold off, perhaps for decades, on the chance that some time in the future you might still be qualified to be a donor to someone, a loved one, who shows no sign of ever needing a transplant now, but might, as anyone might. Paired donation makes your concern about testing for a match moot, and even if it didn't, there's no guarantee you'd still match sometime in the future. I decided that present definitive need trumped unlikely future need, and that if I said yes to donating now, it would reinforce, even just a little bit, the culture of giving we live in, increasing the likelihood that if my loved ones did have need in the future, it would be that much more likely that someone else would come forward for them, then, just as I was, now. You have to weigh these yourself, and whatever you decide is right for you. It is possibly the toughest one. Take care.