Fonts in desktop environment always change across reboots
On my Archlinux, I installed proprietary nVidia drivers because of the presence of an nVidia card.Unfortunately, each time I reboot, I have to set the fonts through the desktop environment in order to have the correct font size.
It's a DPI detection problem
According to some community posts, it has to do with DPI detection- http://www.techytalk.info/lubuntu-change-fonts-dpi-when-using-proprietary-nvidia-driver/
- http://www.linuxquestions.org/questions/linux-general-1/installed-nvidia-now-everything-is-huge-853657/
- https://ubuntuforums.org/showthread.php?t=2201820
- https://bugs.launchpad.net/ubuntu/+source/unity/+bug/1310316
Hard seting the DPI
The solution I choosed is to edit "/etc/X11/xorg.conf" and addOption "DPI" "96 x 96"
in the "Monitor" section.
The "Monitor" section becomes:
Section "Monitor" Identifier "Monitor0" VendorName "Unknown" ModelName "Unknown" HorizSync 28.0 - 33.0 VertRefresh 43.0 - 72.0 Option "DPMS" Option "DPI" "96 x 96" EndSection
Don't touch other sections unless you know what you're doing.
Reboot and enjoy.