There is no specific legal deadline for carrying out executor duties. However, an executor does have a fiduciary duty to the estate and the heirs--a duty to act faithfully and reasonably/prudently in their interest, and a concommitant duty to not engage in "self dealing," or putting her interests ahead of the wishes of the deceased or the interests of the heirs. If, as you suggest, your sister is deliberately delaying things to prolong how long she lives in your mother's home, she would seem to be violating her fiduciary duty; you could bring a legal action in surrogates or probate court requiring her to "account" for her actions as executor and seeking some combination of compensation for the heirs & estate and/or a court order setting deadlines for her to complete her duties. Such an action is considerabley more complex than, say, suing in small claims court over a promissory note or unpaid invoice; you are advised to retain an attorney to help you.