Best way to check if a field is changed upon update to run a


So I have a settings table with a boolean column in it. It is mostly
1, but in the case it changes (either way) I need to run a method via
an after filter. This is probably an easy answer but I want to know
whats the best way to check in my after filter method (or should I do
this test elsewhere? Maybe in the actual update statement?) whether
the boolean field has changed from what it was? Thanks.