1) she is entitled to 7 days after 1 year, but both parties must agree when to take those 7 days or give money in lieu. She cannot force u.
2) never pay her airfare till contract ends, otherwise Immigration will ask for it a second time
3) never advance money or ticket as a loan as she may not come back
4) If u really let her take a vacation, ask her to sign a letter saying she has taken x days of annual leave already. If she does not return by (date), then you will deem she has broken the contract and owe you one month's pay in lieu of notice. Then you are free to hire a new maid to replace her and throw away her personal belongings.