We have a wonderful girl who comes in twice a month, the first couple times I was home- in my sewing room staying out of the way. She does a great job & now we don't worry about leaving or not being home when she comes in. It is best to meet with the person you are considering, discuss what all you want done, how long you think it should take, what you will pay, any areas that are off limits.... If you are not totally comfortable with the person for whatever reason, don't hire them, look for someone else, if you find you really do like the person ( good vibes/ bad vibes)
Give them a try. Be home the first couple times, but not in the way, don't*hover* watching every move- that will make both of you uncomfortable. Before they leave do a ( glance over- walk through) if anything is not done gently point it out, if everything is great let them know ( wow, great job, thank you, see you on....)
Remember everyone finds their own methods to do things, don't expect a person to do everything exactly how you do them, do expect a good job, final outcome to measure up to your expectations.