You should leave some free space on your solid-state drive or its write performance will slow down dramatically. This may be surprising, but it’s actually fairly simple to understand.
When an SSD has a lot of free space, it has a lot of empty blocks. When you go to write a file, it writes that file’s data into the empty blocks.
When an SSD has little free space, it has a lot of partially filled blocks. When you go to write a file, it will have to read the partially filled block into its cache, modify the partially-filled block with the new data, and then write it back to the hard drive. T…