Being a longtime user of secondhand computers has taught me two important lessons: 1) don’t depend too much on the computer (as if my entire life would come to a halt if it breaks down), and as much as possible, be always prepared to transfer my work on another unit; and 2) always have backups of my important files, both in USB drives and DVDs.
Furthermore, being a longtime Windows user has taught me another important lesson, and that is, to never build some important works that are fully dependent on the operating system itself (and other commercial applications). And that is because, some years down the road, the OS will inevitably and drastically change (and so do the applications built on it), and it will most likely leave my works obsolete. (Therefore, all my investments of money, time, energy, and creativity will be lost!) Mind you, I’m not a power user or a programmer, but this affects me as a regular user nonetheless. Just imagine the vast amount of computer programs ever written (and all that went into producing them) that have become unusable because the systems they were built for are now no more.