Broadband.

Indeed - I had fears that BT ownership would knacker them, but they do seem to have retained most of their original advantages.

When BT purchased Plusnet, they told them that although they owned then they would still be able to operate without any interference from them. I forget the exact wording but in a nutshell that is what they meant, which is probably why they have such a good reputation.

I have 4 ADSL lines, and I have found that the modems do seem to have limited life. Some die completely, but others just drop in performance. If you have one which is over 4 years old, you might want to think about changing it anyway.

I certainly don't have your experience of ADSL gear, but for most hardware that would be rather odd behaviour. Do you know of any mechanism which would explain it? Leaky electrolytics seem unlikely. Some kind of accumulated malware might explain it, but that also seems unlikely.