Reintialize to the default value of a checkbox

I have a multi-tab subform on my main form. On two of the tabs, I have a
checkbox (not related to each other). The default value for each of them is
off. They are not bound to a database, they are simply used in a calculation
launched by a button on each tab. If I click the checkbox to set it to true,
if I go to a new record, it retains the reset value instead of returning to
the "off" state. How can I can get the checkbox to reinitialize either when
I switch tabs, or when I switch records entirely?