Shemoneh Esrei-Yaaleh Veyavo:

One Davens a regular weekday Shemoneh Esrei for Maariv, Shacharis and Mincha, although adding Yaaleh Veyavo to the prayer. If one forgot to recite Yaaleh Veyavo in Shemoneh Esrei he must repeat the prayer. This applies even by Maariv.

Forgot Yaaleh Veyavo but remembered prior to finishing Shemoneh Esrei: If prior to finishing Shemoneh Esrei one remembered that he did not say Ya’aleh Veyavo, [then if he is holding prior to saying the name of Hashem in the concluding blessing of Visechezena then he should say it as soon as he remembers and continue afterwards from Visechezena.  If, however, he remembered only after he already said Hashem’s name in the concluding blessing of Visechezenu then some Poskim  rule he is to conclude the blessing with Lamdeini Chukecha and then go back and recite Ya’aleh Veyavo and then repeat from Visechezena.] If he remembered after concluding the blessing of Visechezena, but prior to Modim, then he is to say it there [and continue afterwards with Modim]. If, however, he only remembered after he already began saying Modim then he must return to Ritzei and recite from there with Ya’aleh Veyavo.  If he only remembered after he already finished Shemoneh Esrei then he must return to the beginning of Shemoneh Esrei. [This applies even if he remembered after reciting the second Yehi Ratzon, prior to taking three steps. ] If, however, he remembered prior to reading the second Yehi Ratzon  then he is to return to Ritzei.  [If he is accustomed to add prayers after the second Yehi Ratzon, then if he remembers prior to concluding these prayers he is to return to Ritzei. ]

In doubt if said Ya’aleh Veyavo: If one is in doubt as to whether he recited Ya’aleh Veyavo then some Poskim rule he fulfills his obligation and is not required to return to Ritzei or repeat Shemoneh Esrei. Others however rule that it has the same law as one who did not say Ya’aleh Veyavo and he must hence return to Ritzei or repeat Shemoneh Esrei. Practically, one is to complete the Shemoneh Esrei and repeat Shemoneh Esrei as a Nidavah. 

If one remembered only after he already Davened Musaf: If one had already Davened Musaf and only then realized he had forgotten to say Ya’aleh Viyavo in Shemoneh Esrei of Shacharis, he does not need to repeat Shemoneh Esrei.