I buy used laptops all the time. A laptop will continue running well over a decade. In fact, the one I'm typing on right now is at least 14 years old. The machine is not important - the application is everything,
A 14 year old machine will run office applications, email, music, simple website like this one, and compressed video like Youtube. Music and file management all easily done with older machines, and having the latest versions of these applications is typically not at all necessary. MS Word is a prime example because so few people ever use the advanced features of MS Office applications. It's also just good practice to save office documents in versions compatible with 2003 and later if it will not negate any feature of the content. (That being said - you still need a way to open files sent in the latest format. This practice presumes you own more than one computer.)
For a DJ - older versions of DJ software are valuable if you are not doing video or any of the advanced things that require the latest versions. That means old Laptops make great music players. I still have a few XP machines that do nothing but run karaoke using older versions of applications. That significantly lowers the cost of software, hardware, and backup because at $200 (
? ? years ago) buying two identical used machines was very affordable. (These are the last 2 of 8 machines and are likely 20 yrs old - still running because the application they are put to remains unchanged.)
My two used i7 laptops were both under $400. My original new i7 was $900. (I won't do that again!) These are the machines that I use for graphics, editing, video, and the latest versions of applications and PDF editing. I enjoy the economy of matching machines to what it is I expect them to do. It also provides multiple layers of backup because I'm not relying on any one machine to do everything.
Music management requires very little processing power. If music players or file management is all you require then that can easily be done with older machines. Just take care to figure in the cost of a new battery because used machines will need one, almost every time. Corporate and Educational users tend to flip their computers right about the time the batteries have reached end of life. Also, the power supplies provided with used computers are usually switched out by liquidators. It's not unusual to receive a 65W or 90W power supply for a machine that requires 230W. The machine won't function properly if it's power supply is weak and the boot warning about this will have been turned off by the reseller. To the uninformed user it looks like the machine is a lemon but, it's actually being choked by a lack of power.
