Topics on xenforo after 59 minutes look old because they are timestamped.
By having "6 hours ago", "4 days ago", the posts look more fresh than just a time.
This is likely a simple few lines of code, and I had a go on the thread, but I've got lots to learn with this sort of stuff.
Any chance of an addon from one of you lovely people? It would sure be useful to me anyway.