She does not need to pay khoms for the items she bought and used in the same year, except if she used them once, and decided that she will not use them again any more in the same year of purchase.
She needs to pay the khoms of such items, if they have market value, as used stuff.
If she do not remember that she went across such situation, she does not need to bother.
Now, since she started work, the day she started to work becomes her khoms day. Hence, she needs to see her saving (balance) throughout the year, on the same day annually, and pay its khoms.