It is well-known among Wikipedians that "Notability is not temporary" and it "does not degrade over time". This may be true, if one assumes that entropy does not exist. For the purposes of a deletion discussion, for instance, you should probably assume that Wikipedia will indeed last forever with no problems and nothing will stop us from carrying out our noble mission of spreading only the knowledge that we deem worthy.

However, this line of reasoning ignores the fact that entropy DOES exist, Wikipedia will not last forever, and we are all inevitably going to die and/or be erased as the universe collapses beneath us. Even if this does not happen, all the websites in the world will die, including Wikipedia, and then it will be impossible to cite any sources or prove that anything is notable because there will be no sources.

Therefore, while notability may not strictly be temporary, it is also true that notability is not eternal. However, you shouldn't care about this.

• Wikipedia:The world will not end tomorrow
• Wikipedia:There is no deadline
• Wikipedia:Notability does not degrade over time
• Wikipedia:What notability is not#Notability is not permanent (This, but written seriously, for boring editors)
• Wikipedia:Terminal Event Management Policy