[keikobadthebad]

Today it really boils down to the buyer accepts the work (usually work done in the period) as reasonable and pays for it, or not. Sometimes there are contractual requirements to make good on bugs afterwards on your own time. But often the hirer accepts the risk of bugs needing solving.

This sounds like there might be extra requirements for an unending? unspecified? period, I don't see how anyone can make a living if so.

[Vespasian]

This kind of liability is not new Europe. In fact it applies to a lot of products. Therefore similar (though obviously not identical) questions are already settled law.

As a layman it may be similar to the questions of how long a manufacturer can be held responsible for material fatique under regular use?