For daily use. I would say the limit is 2010, before that it is difficult to use unless it is for a specific function.
That I can use on a daily basis, I have a MSI GE 65 from 2012, 2.3 GHz pentium 7 (3rd generation) with an Nvidia 660m, I have it with Ubuntu and it responds well to perform daily tasks today (upgrade RAM and change HDD for a SSD). Unfortunately it has started to give problems, it turns off randomly and I suspect it is the motherboard, so it does not have much useful life left.
I have an Acer C100 with Windows XP tablet edition, I think it used a Pentium III mobile. The computer is from 2005 or so and due to the OS and limited hardware, it cannot be used today.Non PC, I still have and use a "palm zire" as a graphic calculator, which must be from the early 2000s.