Limitation of Terraform (Azurerm provider)


I want to ask, if anyone could give me some information about limitation of Terraform or Azurerm provider. I searched internet and docs about this information, but unsuccessful. Now I have state with 1200 resources via Azurerm provider and in future I want to split it into smaller states, but it would be nice to know, when it will be critical, because changing one big state into smaller is not so easy. I understand that you can not give me specific number and it depends on multiple factor, but any hint will be helpfull.

Thank you very much.