I bought one of the original Tesco Hudl tablets last year, and it's done exactly what I need it to at a fraction of the cost. I don't really play games on my phone or tablet... that's why I have a PC (also used for work).
It still does what I need it too... So the only reasons I can see for anyone to replace their tablet are thus.
1: They're the lame types that 'have to have' the latest stuff regardless of whether what they have is still of use.
2: They want Android Lollipop
I like my gadgets, and I like to get new ones when I can... However I don't believe in wasting money on replacing stuff that works perfectly well. If anyone I know makes any attempt to point out that what I have is 'old'... I simply mock them for their gullible devotion to consumerism and suggest that if they don't already own one... to buy something from Apple like the good little sheeple they are. :)
My phone was released in Nov 2010 and still works well, does everything I need it to and when it breaks, I'll replace it. My computer was built in 2010, and because I looked ahead and invested in Xfire graphics, still plays anything I throw at it in full HD.
The only thing I was considering replacing was my TV, it's only 32" and was bought so long ago that it's 720p and 1080i... and I do so much now that requires proper 1080p. But as I was given another 32" that is 1080p... theres no need to replace it at all and the old one was put to use in the bedroom.
The one thing that does bug me about the Hudl though, and it goes for every phone manufacturer out there... and this could be the best and most honest reason to change a device... Manufacture bloatware and refusal to upgrade the OS on devices.
I've suffered from this and it pisses me of a great deal... So much that when I do need to replace my phone, the only alternative I would consider is a Nexus device... the same goes for my tablet.
But NOT because they are the new 'shiny' gadget out there, but because of the lack of bloatware and the speed at which updates become available... I don't imagine I'll be doing any of that soon, I have better things to spend my money on than the latest toy that isn't needed.