In this thread, I would like to discuss: "which is more natural for a simple cosmological model: taking the long term Hubble time as a timescale (as Marcus has done), or taking the Hubble time as a timescale". I will start by paraphrasing Marcus' OP and replacing his '##\Lambda##-timescale' with the '##H_0##-timescale'. Here is the 'paraphrased' post: If this seems to be a valid approach, we can jump to the next level of equations developed in the original thread. [Notes] 1. If we use negligible matter in this model, i.e. essentially just ##\Lambda##, the long term Hubble time would have been around 14.4 billion years. The actual long term Hubble time depends on the ratio of spacetime curvature caused by matter to the spacetime curvature caused by ##\Lambda##. 2. The basic equation is from George Jones in this post, where he wrote it more specifically for the cosmological case:  My concern as expressed in Marcus' thread is that beginners may be confused by the 'new' natural timescale. I understand that in the end it might be a case of personal preference, but maybe there are more opinions about it.