Do I need to re-submit all documents to extend my marriage visa in Thailand?

When extending a 1-year marriage visa in Thailand, you will need to submit all the same documents again, similar to your initial application. There might not be simplifications despite previously holding the non-immigrant O visa; the process generally requires the same documentation, including bank accounts and household evidence. It's advisable to prepare copies of your documents and check with your local immigration office for any potential additional requirements.