best place to put export variables

[Mihai Popescu]

Hello,

I want to export XDG_CACHE_HOME variable used by Xorg.
What is the best place (file or ?) to export this variable?

I remember i used some file to export a long time ago PS1 variable.
Should I use ~/.login file or is it a better way to export this xorg variable?

OpenBSD amd64 here, snapshots install.

Thank you.