> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://help.taxx.lu/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# When should I complete Form 166?

You can complete Form 166 at any time during the year.

Once the form has been completed, signed and sent to your RTS Office, you will receive a new tax card within +/- 1 month.