my house line (Telekom) already 20+ years ... I was thinking to replace the whole cable (from external pole -> internal phone jack) ...

total length is ~10-15 metres (i think this is the average cable length)?

any ideas how should I proceed; as in...

1) how much is the charge?
2) how long to replace? hours? days?

Reason to change: Cable too old, i'm suspecting my streamyx line affected by it

1Mb account, but max down speed is avg. 100K = 80% bandwidth <-- is this normal/avg or should I get higher?

thx for the info