Hi, I'm still currently using a Mac Pro Mid- 2010 and it has a total of 250 gb and I've used around 150 gb. I've never used time machine before and prior the update of OS X Sierra I'm planning to back up my files. Due to budget, I am not planning to buy Apple Airport Extreme or Time Capsule but going to buy an External Hard Disk. How big should the external hard disk be? Could it be a 500 gb hard disk drive?
Thanks