Q: Can I demand a reward for returning the aveidah? Whose aveidah takes priority?

A: You are required to return lost items without charge, even if the hashavas aveidah requires time and physical effort on your part, as with any other mitzvah. You may not demand a reward for returning the item. If the owner offers a reward, though, some permit taking it. Others recommend that you tell the owner, “It’s not necessary,” but allow taking if he persists, or that you give the reward to tzedakah (C.M. 265:1; Hashavas Aveidah K’halachah 10:2; Teshuvos V’hanhagos 3:463; Pischei Choshen, Aveidah 8:[1]).

Nonetheless, you are not required to suffer monetary loss for hashavas aveidah. Therefore, your own aveidah takes priority over someone else’s. This is true even if his item is worth much more than yours and he promises to compensate you for your item. A person should not be particular on this point, though, and should help others unless he will suffer a clear loss (C.M. and Sma 264:1).

By law, a person’s own aveidah takes priority over his father’s. His father’s aveidah takes priority over his rebbi’s nowadays, since we have multiple teachers and pay tuition (C.M. 264:2; Shach 264:1).