To keep the software permanently on your machine without it expiring, you must use a valid license:
If you don’t have a valid license, Autodesk no longer sells AutoCAD 2018 — you would need a newer version or a subscription. Autocad 2018 Download And Install Permanently
Alex navigated to the Autodesk website and found the AutoCAD 2018 product page. He clicked on the "Free Trial" button, which allowed him to download and install AutoCAD 2018 for free. However, the trial version would expire after 30 days. Alex wanted a permanent installation, so he looked for other options. To keep the software permanently on your machine
Would you like help finding legitimate free alternatives to AutoCAD (like DraftSight, LibreCAD, or NanoCAD) instead? or NanoCAD) instead?