It is never necessary to upgrade/change your Operating System if the one you have works and does what you need it to do....but there are caveats.
There are many factors that can ultimately force you to upgrade other than the hardware support for the devices in your PC.
If we assume this PC is being used to browse the web, create documents, send/receive email (i.e. general type use), then compatibility issues with the browser, software used to create documents, etc can all require upgrades over time and eventually, the newer versions of that software will also require an upgraded Operating System.
Older OS's are no longer getting supported...that means security patches and updates are not being created. While that may not directly impact its use, it does make it potentially more vulnerable to hacking.
Newer OS's on older PC's may, or may not perform well (or at all).
You need to decide if Windows 7 is viable for you and understand that it reached end of mainstream support in January of last year. If you are a little diligent with your anti-virus regimen and pay attention to keeping your system clean, Windows 7 will be quite usable for several years to come.
Since you are using a Quadro card, I assume this is an older or lower end workstation and you are doing CAD, or have a need for higher res multi-display set up? In your case, I'd be more interested in upgrading the system as a whole over worrying about Windows 7 vs 10.