org-agenda-max-effort

org-agenda-max-effort is a variable defined in `org-agenda.el'.
Its value is

nil

Documentation:
Maximum cumulated effort duration for the agenda.
This can be nil (no limit) or a number of minutes (as an integer)
or an alist of agenda types with an associated number of minutes
to limit entries to in this type.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.4 of Emacs.