The Laws of Prayer /Verses of Praise (34)

1. A person should be very careful to be punctual about prayer, so that he will not have to omit any of the prayers or to change the order of the prayers, as in this order there are hidden many great and wondrous secrets. (Mishne Berurah and Kaf Hachaim 52)

2. Even in those cases when one is allowed to omit portions of the prayers, this is only when a person arrives to pray with the congregation, and this is only quorum. If, however, there will be another quorum later, he must wait for that one. (Kaf Hachaim)