Interior plaster with or without mesh - Can it form without cracks?

Hello everyone,

in my construction specification under interior plaster it says: "Note: Hairline cracks in the plaster can occur according to DIN in new buildings and are therefore not a building defect:"

Now my grandfather said that it is possible that the builder does not embed mesh and without mesh cracks are more likely to occur, and that is why he includes this statement. So basically he builds cheaply in this area and protects himself with this text. If he were to embed mesh, no hairline cracks would occur?
What is common nowadays? What makes sense?

Oh, by the way, a smooth machine gypsum plaster will be applied.

PS: The same text is stated for the exterior plaster. But I strongly assume that reinforcing mesh is used there. (It will be an ETICS with mineral wool)

Best regards
Dennis

What quality level is being discussed?
Q2 states that it is suitable as a wallpaper-ready substrate/plaster. That means if you don’t wallpaper, you will see hairline cracks.
If you want everything reinforced, you can certainly upgrade to a correspondingly higher quality level for an additional charge.
Otherwise, you have to live with the hairline cracks.
Your construction service description is a reflection of your house price. In principle, you can order upgrades everywhere. However, you could also consider in advance whether it might be more sensible to choose a BU that builds at a higher cost but with better quality features.

Oh, Q2, but with the gypsum plaster there's no big difference to Q3 anyway, I was told, so you could just paint over it right away.

I don't really understand the connection between quality level and reinforcement. Is Q3 always with reinforcing mesh?

I know I can order upgrades everywhere. It's just a question of whether it's sensible.
Why should I change the BU right away now?

So indoors, one always does without fabric plaster, everything else is beyond the state of the art and established practice. And you have to live with small cracks, almost all new buildings nowadays have them. If larger cracks occur, remedial work must be done afterwards.