274. The Time for Musaf and Maariv

Tefillah u’Birkas Kohanim 3:5

The proper time for the musaf service is from after shacharis through seven hours of the day. If a person recites it after seven hours, he has acted neglectfully but he nevertheless fulfills his obligation because the time for musaf is the entire day.

Tefillah u’Birkas Kohanim 3:6

Even though maariv was not originally considered obligatory, a person who recited it had to do so in its proper time, which is from the start of the night until dawn. The proper time for Ne'ilah is so that it is completed close to sunset.