WARNING: SPOILERS AHEAD
I'm rewatching Buffy at the moment, because of course.
In season three, Giles is fired by the Watchers' Council. Presumably, the Watchers' Council pays its watchers, because otherwise Wesley would have to have a second job. Assuming that watchers are paid, Giles has been collecting two salaries for at least three years (school librarian + watcher).
At the end of season three, the school burns down meaning that Giles is no longer employed as a librarian. In season four references are made to him being unemployed now. Yet he doesn't seem to be in a hurry to get a job at all - instead living what appears to be a happy, comfortable life - and has enough extra cash to pay Xander for extra work around the house.
Later, he buys the Magic Shop, so presumably has enough cash on hand to purchase a business with at least a sizeable deposit.
I vaguely recall that at some point further on (season six?) he gives Buffy a generous gift to assist with her home repair and living expenses.
So: do you think Giles is FI? And did anyone else watch the series and pick up on his apparent lack of any need to be employed?. I didn't notice it when I watched the series previously, but then, early retirement wasn't at the forefront of my mind back then.