I have no experience with SSD, but running my Debian Desktop from a USB
Memory Stick since years, please allow me to share information which
supports the suggestion of Linux-Fan to also investigate if there is
extraordinary I/O taking place and maybe could be avoided:
In the past I found extreme(!) I/O to be produced by Firefox, when it is
writing its cache, and when it is writing its session restore
information. These writes to my observation occure all the time, kind of
nonstop! I could get it very satisfactorily reduced by applying a tool
called "Profile Sync Daemon" (psd) from package "profile-sync-daemon".
While it is packaged for Debian, as a starting point to study its
documentation I suggest to better look it up in the Arch Linux Wiki.