I've been through the upgrade process myself and can share a bit about it. When it comes to costs, upgrading from Windows 10 to Windows 11 is indeed free, provided your current system meets Microsoft's requirements. That was a relief for me since I didn't want to deal with extra fees.
The tricky part can be the hardware requirements. Windows 11 needs things like TPM 2.0 and Secure Boot, which generated a bit of buzz when the OS was announced. Like many others, I found the PC Health Check tool useful—it quickly checked my system for compatibility, so I'd recommend giving that a go if you haven't already.
In terms of personal experience, my upgrade went smoothly, but I did make sure all my data was backed up just in case. If your system doesn’t meet the requirements, you might have to weigh the costs of upgrading hardware against sticking with Windows 10 until Microsoft phases out its support in 2025.
If you have specific concerns about your hardware compatibility or any software you're using, it might be worth checking those against Windows 11's requirements and support pages. Keeping everything backed up and making sure all your software has updates compatible with Windows 11 can help minimize any hiccups during the transition.