The Sefer Hahasidim (by Rabbenu Yehuda Ha’hasid, Germany, 12th century) writes that one should not wear the shoes of a deceased person. If the inheritors put the deceased’s possessions up for sale, one should not purchase the shoes to wear them. The Sefer Hahasidim tells of a certain individual who wanted to give a deceased person’s shoes to a poor person, who could not afford proper footgear. His peers then reminded him of the famous commandment, "You shall love your fellow as oneself" ("Ve’ahabta Le’re’acha Kamocha" – Vayikra 19:18). Just as he would not want to wear the deceased person’s shoes, similarly, he should not give those shoes to somebody else. He was therefore advised instead to sell the shoes to a gentile, and then give the money to the needy person.
It should be noted that one should not sell the gentile a deceased person’s shoes if there is a good chance that the gentile may later sell them to a Jew.
This Halacha is very relevant to Jewish clothing charities and the like, which occasionally receive the clothing left behind by a person who passes away. One must ensure not to donate a deceased person’s shoes to these charities.
The Kaf Ha’haim (Rabbi Yaakob Haim Sofer, Baghdad-Israel, 1870-1939), in Siman 116, writes that one must not sleep while wearing shoes. Based on a comment in the Talmud, the Kaf Ha’haim writes that doing so is tantamount to "tasting the taste of death," Heaven forbid.
The Talmud warns of a number of different situations that pose the danger of potentially causing a person to forget his Torah knowledge. One such situation is switching shoes – wearing on the left foot the shoe normally worn on the right foot, and vice versa. This might not seem so applicable nowadays, when shoes are made to fit only the right foot or only the left foot, but it occasionally happens that a person must run outdoors for a brief moment and thoughtlessly throws on his shoes or slippers. He must ensure to wear them on the right feet, as wearing shoes on the wrong feet for even a brief moment could potentially cause one to forget his Torah learning. We experience enough difficulty as it is retaining whatever knowledge we acquire, so we certainly want to avoid any situations that could cause us to forget even more.
Summary: One should not wear the shoes that belonged to a deceased person, or give them as charity to a fellow Jew in need. They should be sold to a gentile, and then the funds may be transferred to the poor. One should not sleep while wearing his shoes, and one must ensure not to wear his shoes on the wrong feet, even for a brief moment.
