How did Michah persuade him to stay with him?
Malbim: He pointed out three benefits. (a) You will stay here, and not be transient. (b) You will have an honorable that relates to your honor - you are a Levi, and you will be a father and Kohen to me. (c) You will get wages - money, clothing and food.
How long is "l'Yamim"?
Rashi: It is at the end of a year.
What is "Erech Begadim"?
Rashi, Targum Yonasan: It is a pair of outfits that is for people, according to their standing, for a year. Radak - one is for winter, and one for summer.
What is the meaning of "va'Yelech ha'Levi"?
Rashi: He followed Michah's counsel.
Radak: He went for Michah's needs, for what he commanded him, and agreed to dwell with him.
Malbim: Initially he did not want to hire himself for idolatry, and he left him.