To be exact, then yes, any 'joint' is a potential failure point. But if you take into account the hundreds of 'joints' already in play on some very long 'DEL's', a couple more to get VDSL services won't matter a jot IMHO.
Glad your sis (and many, many others) will benefit from this re-engineering of OR plant, Chrysallis. I have to admit to being puzzled at the decision to make 'Close to the Exchange' DEL's into FTTC, thinking it would only be the far-reaching rural ones. But, it's a win-win for the likes of your sis who wants more speed, but could probably survive on the 24Meg anyway ??
One particular rural exchange area on my patch will be overjoyed by this new work, though. There are
NO Cabs at all with every EU being DEL.
![Smiley :)](https://forum.kitz.co.uk/Smileys/kitzemotes/smiley.gif)