Well, not just sockets... If during construction I thought we could shift the window a bit, this was still possible without extra charge with colleagues currently building because it only turned out to be "nicer" on site...
And I still believe with some work you can save a certain amount...
Offer 1 suggested 4 weeks of helper work in the shell construction (cutting bricks and such things) would be compensated with about 3k...
We live very rurally... People still help each other a lot within the clubs among colleagues
Edit:
We also once spoke with a prefab house company from around here - lead time currently at least 1 year... And in that time I can also have one built brick by brick