What is a Headshell and what does it do ?

If you plan to have 2 different cartridges with same VTA and VTF when mounted, than you just swap'm. If you plan to use another cartridge let's say for 78rpm records, regardless of VTA and VTF it probably wouldn't matter

At a minimum, you're generally going to have to adjust vertical tracking force for each cartridge, and usually anti-skating as well. Most cartridge have their own individual sweet spot within the recommende tracking force range.

Not mentioned up to this point, but it's waaaay easier to mount a cartridge on a detachable headshell AND significantly lower the risk of damaging the cantilever during the process.

Johnny53 ;
Is a "detachable" headshell different than what has been discussed so far ? Would it still be required to check the angles as mentioned above when swapping two of them around ?

Thank you

note that on some headshells there's the screw hole to mount extra weight. all to match one cartridge to another

You must set up each cart/headshell with a proper protractor (mint, geodesic, or various online printout), VTA, and tracking force. You will then be able to swap out cart/headshells with only a VTF & VTA adjustment ~ and sometimes with only a tracking force adjustment.