What does homily mean?
A tedious moralizing lecture or admonition.
The readings end with the Gospel, which is followed immediately by the Homily. Right after the Homily the priest and congregation renew their faith by reciting the Nicene Creed (at most Sunday Masses and Solemnities). On a weekday that is not a Solemnity (major feast) the homily would be followed by the Intercessions.
On weekday masses a homily is highly encouraged but not mandatory. Thus a priest may lawfully choose not to preach on a weekday mass. However, on Sunday and on Holy Days of Obligation a priest is never permitted to omit the homily. A priest may choose to give a short homily, but it is never permissible to omit the homily.
Roman Catholic Answer Without a congregation and a homily, a private daily Mass would normally last about twenty minutes, with a congregation and an optional homily, it would be determined by the length of the homily, a usual daily Mass may run anywhere from twenty-five minutes to forty-five minutes, although I know one priest that regularly runs longer.