I'm waiting to see what happens when BT convert my phone. Shouldn't be difficult. There's an extension, wireless base, ADSL router and handy powerpoint. As my landline and broadband are both BT provided, I'm expecting BT to replace the copper line (from pole to house, easy access) with fibre and give me a new router and handset. Or maybe just a router and I have to buy an IP handset. The switch-over should be seamless except for me having to connect all my computers to the new router.
My mum is a bit more complicated because she has a big button phone that she can see and understand, an ADSL router set up by me, and a red-button alarm box. There's a power socket, and I think the red-box has an ethernet socket. With luck it's ready to go, otherwise the red-button device will have to be replaced, hopefully on the same day. I expect I'll have to attend to make sure it all works and buy a new big-button uncomplicated IP phone that mum can cope with. I have an idea grannie-friendly phones are pricey.
Worst case I suspect will be anyone who finds change difficult, has a complicated internal copper set-up, no power-point where the cable comes in, and lives in a hard to wire home.
I've long passed the age where I resent change being forced on me or my technically hopeless family members. They all look to me to make thing work! Should have kept my hobbies secret!!!
Dave