Is it correct or incorrect for some people to assume ihram for Hajj from the Grand Mosque on the Day of Tarwiyah, without changing the ihram garments they wore for Umrah?

Among the mistakes in assuming the state of ihram (definition) for Hajj on the Day of Tarwiyah is the belief by some that it is obligatory to enter ihram from the Grand Mosque, whereas the Sunnah (definition) is to enter ihram from one's dwelling place, as the Companions entered ihram from their respective locations. Another mistake is the assumption by some that the ihram is not valid with 'umrah (definition) clothes unless they are washed, while the correct view is that this is not a condition, even though cleanliness is preferable.