You must use it only for home-based, personal design or manufacturing projects.
If you use a CNC router, you lose the "probing" functions. You must manually set your Z-zero, which is tedious but not impossible. fusion 360 personal
However, if you are serious about moving into product design or sending files to machine shops, the lack of and multi-sheet drawings will eventually force you to pay. Autodesk is betting that you will fall in love with the workflow and upgrade. You must use it only for home-based, personal
You must generate less than $1,000 USD in annual revenue from your projects. 000 revenue ceiling
Download it. Learn it. The second you hit that $1,000 revenue ceiling, buy the commercial license. Until then, enjoy the most powerful free tool in the maker's arsenal.