This is probably the most stated comment since the expiry date. We find a lot of customers didn't upgrade because they heard Windows 10 was unstable or had bad feedback. We totally agree, Windows 10 on it's release was pretty shocking although we felt it was a lot better than it's previous releases Windows 8 and 8.1. After a few patches came out, Windows 10 became quite stable. It had it's odd Windows update failure resulting in a lot of machines having to be re-installed, but overall it was a solid OS and advised by Microsoft to be the 'final' release of Windows and that future updates would be patches and feature pack releases.
Like any out of date software, it doesn't just die on the expiration date, although a lot of 3rd party vendors have been concentrating on Windows 10 for some time with the pending end of life of Windows 7. It will continue to work for a lot of apps and Internet browsers, but over time the security of the whole platform will be challenged. I guess the question is 'What do you do with your computer?' If you use it for games and watching on-line videos without doing any form of purchasing or banking, then the data you are risking will be down to social activity and passwords that you use for accounts like YouTube or Netflix. The risk is much lower than someone who buys of Amazon, eBay or banking.
Do you want to risk your data being exposed ? I don't think anyone would want this to happen, but for a lot of us, we don't hold anything financial on our computers for fear of cyber crime and identity theft.
If your computer is powerful enough and you don't have any problems with compatibility, you should move to Windows 10 ASAP. You should bear in mind if your computer is 5 years old or more, it might be an upgrade isn't the best option for you; there are plenty of refurbished computers available at almost half the cost of a new one that will be money better spent.