In my many years of dabbling with computers, one good idea I’ve come up with is to take photos of your hardware.
Because you might be browsing for a new sound card at the stores but can’t remember if you have any available PCI slot to use.
You might come across an article one day that claims that a batch of SSDs are faulty, and you end up having to open up your PC to find out the serial number of your SSD to see if you’re affected.
Keep them stored on your phone and dropbox so it’s easily accessible.
A folder of links to your hardware’s details on their manufacturer’s website is useful to keep too. So you can easily check for any new BIOS updates or look up specs.
Digital copies of receipts and warranties too!
In case something spoils and you want to know as soon as possible if it’s still covered under warranty.
And to save yourself from turning your house upside down to find the receipt of your purchase made years ago, always keep them securely together in a folder at a fixed location.