Regarding this issue, it should be clear that as long as one stays for a long time, two months at lest, then he or she is not allowed to pray Qasr. Instead, he or she has to pray in full. However, while on traveling to his or her hometown or to the city where he or she studies, it is allowed to pray Qasr during traveling if the distance is 80KM or more.
Giving detailed elaboration on this, Sheikh Ahmad Kutty, an Islamic scholar asserted:
“1) There is a general consensus among scholars that if a traveling person is determined to return as soon as his work is done and does not know when that will be, then he may continue to pray Qasr as long as he is on travel.
If, however, a person decides to settle down in a city, the moment he does so, he ceases to be a traveler, and, therefore, he must pray full.
If, on the other hand, one is determined to stay only for a few days the number of which he knows precisely, then he should pray full, according to a great number of scholars, if his stay exceeds more than four days. The Hanafi School, however, puts the number of allowable days at fifteen, while a third group of scholars put it at eighteen.
The first view seems to be the safest view to follow, as it has been based on the Prophet’s practice.
According to authentic reports, he stayed in Makkah for four days, and during his stay he prayed Qasr; he had already known in advance how many days he would be staying. He is reported to have prayed Qasr for eighteen and twenty days on two different occasions, when, most likely, he had no idea as regards the number of days he would be staying.
Having said this, I should rush to state that if anyone follows the position of the Hanafi School, he should not be blamed for his action, for theirs is a Fiqh– ruling based on acceptable practices of the Salaf as-Salih (pious predecessors). Since it is merely a question of differences of interpretation based on valid Ijtihad (creative exercise of reasoning), one should never make a big issue out of such differences of opinion among Imams.
2) The most accurate way to count the number of days for a traveler is to consider oneself a Musaafir (traveler) only after one has crossed the boundaries of his city of residence. Thus in case of people living in Toronto, if they are in a long distance journey they will be considered travelers only after they have crossed the boundaries of GTA. The days of stay are calculated by excluding the day/days of going and returning.”