Best way to organize variables that are used by multiple roles

Hi all,

Our project has several roles that make use of the same variables. Looks like the best practice to organize roles is to place each of these variables in the roles//defaults/main.yml or roles//defaults/main.yml. However, it becomes tedious for a user to change the same variable across several files. What is the best way to organize such variables so that user can toggle it at one place? Currently we do it in group_vars/all.yml, but not sure if that is the best place.

I am not the ansible expert here; my posts here clearly showed that.
What I do is break it apart putting the more global stuff that is
related to your setup in group_vars (ex: all your webservers have a
basic initial setup) and then stuff specific to a given machine might
be in the playbook entry for said machine. Probably it can be done
better.