The Chayei Adam – Rabbi Avraham Danzig (1748-1820), Dayan (Rabbinic judge) in Vilna towards the end of his life – teaches in his first Halacha on the laws of Torah Study:
"It is a positive commandment from the Torah to study Torah, as it says, 'And you shall teach them to your children.' And it is written, 'And you shall teach them.' And it is written, "This shall be the reward when you listen…" There are many other such similar verses.
"Therefore every Jewish person is obligated to study Torah, whether he is poor or whether rich, whether completely healthy or filled with pain (G-d forbid), whether young or very old. Even a poor person who goes around collecting money from house to house, even a husband with children is obligated to set for himself a time to learn Torah – both during the day and at night, as it says, 'And you shall meditate in it day and night.' A person who does not know how to learn should support others who are able to learn, and it will be considered to him as if he was learning himself. A person can make a stipulation with his friend that he should study Torah and he will provide for him his living, and they will divide the rewards of Torah and the reward of livelihood so that they will both profit."
All are obligated to learn. Nobody is exempt. Those who lack the time or who find they cannot understand as much as they would like – and therefore feel the need to concentrate more on work than on Torah – they too can take part in the Mitzvah of Torah study – by supporting those who truly wish to learn and to teach.