How do you decide if you should upgrade to Windows 10 or not? Below is how I would answer that question. This is my opinion and the answer can vary from situation to situation.
Regardless of what version of Windows you have now something can always go wrong with an upgrade. It is a big deal to change your operating system and a lot of stuff has to go just right for it to be a success. No guarantees that all applications and hardware is compatible. For example: there may not be software available to make your printer work with Windows 10. Or you might have to install a newer version of your anti-virus software
REALLY IMPORTANT: If you are currently experiencing problems or if your computer is eat up with viruses and unwanted programs then you should not upgrade until all issues have been resolved. I would not attempt the upgrade unless your computer is clean and problem free.
What if I have Windows 8 or 8.1?
First, Windows 10 is a great upgrade for those using Windows 8 and hate it. Navigation and usability is greatly improved with Windows 10. Microsoft dumped the start screen with all the tiles and they also removed the charms bar that pops out on the right side of the screen. Most important, they added the start menu back and it works great.
What if I have Windows 7?
Windows 7 is still a great operating system and will be supported by Microsoft until 2020. One thing you might miss out on is Microsoft's newest web browser, Microsoft Edge. However, you can always use the latest versions of Google Chrome and Mozilla Firefox on Windows 7. In short, if you are on the fence about the upgrade and are happy with your current setup then I would stay put. Maybe wait until you get a new computer to get Windows 10. It's not worth the risk to upgrade and is okay to stay on Windows 7. If you don't have many applications, or consider your self to be tech savvy, or like to keep up with the latest technologies you might consider the upgrade.
What about Windows Vista and XP?
Windows Vista and XP does not qualify for the free upgrade to Windows 10. I would not spend any more money on Vista or XP. You might consider getting a new computer with Windows 10 already installed.