Yes, generally speaking below 30% is when youre supposed to be "okay" for transplant... but like the other poster said, it really is personal.
For me, I havent been listed, but have already had one consultation at a center and will be seeing them again for an update on me...
i am in the 30s and low 40s generally... but I have been slowly declining pretty much for 2-3 years... BUT I have some bugs that cause concern for transplant, so for that reason, we started looking at transplant "earlier" just so that way I would have a center set up for when "***** hit the fan" (started becoming really resistant, sudden decline in pfts, in general... I was denied by 3 or 4 centers first, before one said that as long as I have 1 or 2 abx left they will do the transplant.
Others b/c of bleeding issues or other issues get listed or start looking earlier than the "30%" ... others I know have been stable at like 26% for like 4 years... so at one time they were listed, but upon seeing no more declining and having a good enough QOL isnt listed and just chilling at 26%.