> I used to think that novelty the key to making time go slow, I now think there is a limit to this.
Yes. Similar experience here. I moved countries at 40. The first few months it feel like being 20 years younger. I wanted to see everything and went around discovering each place possible.
But, I am not young anymore. Nowadays, my new country is my new home and it feel cozy an familiar and time passes faster than ever.
> This also happened to me when spending six weeks backpacking in Europe.
For me it took longer. I have visited Japan 5 times, usually 5-6 weeks each time. I have visited temples, museums, parks, events, ... The last time I spend half of the time shopping. As, I felt that each new temple is similar to the previous one.
Even traveling to South Korea, and China it does not slows time so much. I guess that the similarities with other Asian countries makes my brain feel like "I have seen that one before".
I would be very interested in knowing if the problem is just age or to have seen already many things. Probably a combination of both.