@stefano Regarding "The Internet connection will eventually be interrupted", I think the litmus test is: ANY ONE THING WILL fail at a random time.
Design your systems and procedures such that you can handle that. Preferably by not even noticing; failing that, without significant disruption by having a tested and practiced alternative.
Electricity. Phone lines. Internet uplink. Computer security software vendor pushes a bad update. Whatever.
If you can handle more than one, that's far better.