The basic principle concerning the obligatory prayers for men is that they should be offered in congregation in the mosque; this was the practice of the Muslims at the time of the Prophet (blessings and peace of Allah be upon him).
Imam Muslim narrated in his Saheeh (654) that Abu'l-Ahwas said: Abdullah said: I remember when no one stayed away from the prayer except a hypocrite who was known for his hypocrisy, or one who was sick. But even a sick person would walk between two men and come to prayer. The Messenger of Allah (blessings and peace of Allah be upon him) taught us the Sunnahs of guidance, and one of the Sunnahs of guidance is praying in the mosque in which the call to prayer is given.
The Islamic texts enjoin that, such as the hadeeth of Abu Hurayrah who said: A blind man came to the Prophet (sa) and said: O Messenger of Allah, I do not have any guide to take me to the mosque. And he asked the Messenger of Allah (blessings and peace of Allah be upon him) to grant him a dispensation allowing him to pray in his house, and he allowed him that. When he turned to leave, he called him back and said: Can you hear the call to prayer? He said: Yes. He said: Then answer it.
Narrated by Muslim, 653
But if you try hard to join the congregation, but are not able to do so because of the situation you mentioned, and you cannot find suitable work or study, which will allow you to pray in congregation, there is nothing wrong with you completing your work or your studies that you cannot do without, then catch up with the prayer before the time for it ends, either individually or together in congregation with one another, if you are able to do that.
It says in Mataalib Ooli'n-Nuha fi Sharh Ghaayat al-Muntaha (1/702), discussing excuses which make it permissible not to pray in congregation: if he fears harm to his livelihood which he needs, he is excused (for not praying in congregation). End quote.
And Allah knows best.
Reproduced from Islam QA