Invoice verification, handling defects and withholding

Hello everyone,

Our first payments to the general contractor are due shortly.
I would like to benefit from your experience regarding what you think should be considered during invoice verification, possible defects, and generally about retention, etc.

Maybe there are also things you would handle differently now. I am already aware that overpayment should be avoided, etc. My concern is more about how to handle situations when, for example, things were not to your satisfaction.
Did you, for instance, simply reduce an amount with prior notice? Did you retain the statutory retention? Did you strictly set deadlines formally, or did you always try to pursue all communicative solutions?

Thank you very much for your experience!

Did everything always go smoothly for you? Received invoice, received service, paid, and that was it?

With us, the first payments for the general contractor will be due shortly.
I would like to benefit from your experience on what you think one should pay attention to in the course of invoice verification, possible defects, and generally regarding withholdings, etc.

I would be relaxed about advance payments; I see no reason for precautionary defect withholdings. You can include "a conto - ohne Abnahmewirkung" in the payment reference of the transfer.

Did you, for example, simply reduce an amount with prior notice?

No

Did you withhold the statutory retention?

No

Did you formally set deadlines or did you always try to pursue all communicative solutions?

No, yes

If we had done anything along those lines, the GC would have stopped construction. They wouldn’t have played those “games.”
We were on site every day and communicated with the craftsmen. In conversations with them, we also learned that they were legally well positioned. But we didn’t really have any major disasters during the house construction. At least, I can’t remember any.

Pay for the received services and communicate the defects. In the current construction phase, there is no reason for escalation.