The Rambam (Rabbi Moshe Ben Maimon, Spain-Egypt, 1135-1204), in Hilchot Talmud Torah (1:8; listen to audio for precise citation), describes the obligation to set aside time each day and night for Torah study. He emphasizes that this obligation applies to all men, regardless of financial or marital status, and even to those who suffer from illness, must beg for a livelihood, or are overburdened by other responsibilities. Under extenuating circumstances, the Rambam adds, one may fulfill this requirement through the recitation of Shema each morning and evening. He adds that if one does not have the educational background needed to study Torah, then he may fulfill his obligation by supporting other people to study Torah.
The Shulchan Aruch codifies this obligation (Orach Chayim 155:1; listen to audio for precise citation), adding that one must set aside a specific time for learning each day and keep to this scheduled study session under all circumstances, even if this entails forfeiting a considerable profit.
The Chid"a (Rabbi Chayim Yosef David Azulai, Israel, 1724-1806), in his work Birkei Yosef (Orach Chayim 155), addresses the question of whether one fulfills this obligation if he receives money to study Torah. This question applies to schoolteachers who receive money to teach Torah, and to Kollel students, who are supported to spend their days engrossed in Torah study. The Chid"a rules that one fulfills the obligation to set aside time for Torah only through a study session for which he receives no remuneration. Therefore, even full-time Kollel students must set aside some time each day for a "voluntary" learning session, beyond the regular Kollel curriculum for which they are paid.
Summary: Everyone is obligated to set aside time each day for Torah learning, regardless of his other pressures and responsibilities, and one must keep to his scheduled session without fail. One who receives money to study or teach Torah must set aside time for study for which he receives no remuneration.
