there is no when is the right time. each person makes that decision for their selves here in america. when they decide they may need it they go to social security office and fill in the paperwork (called applications) then social security contacts your treatment providers for information and verify what you you put on the application then social security sends you a denial or acceptance letter based on the information that was provided to them.

if you feel you may need it contact your states office of social security or their website and do the paperwork, see your treatment providers so that they can do their part of the process.