Musnad Ahmad 30:231

Sufyan narrated to us, from Abu al-Zinad, from al-A’raj, from Abu Hurairah: "When one of you puts on his sandals, let him begin with the right, and when he takes them off, let him begin with the left. And if the strap of one of your sandals breaks, do not walk in one sandal; let him take them both off, or let him put them both on."