Why does a listing agent sometimes take a stale listing off the market and relist it as new?

Only pulling a listing off the market for a full 90 days resets the days-on-market clock, so a relist is usually about manufacturing a fresh start. The MLS tracks two clocks: days on market and cumulative days on market. If a home hasn't actually been off the market for at least 90 days, canceling the listing and putting it right back on carries the same cumulative figure forward, so nothing resets. An agent who wants the home to present as new has to wait out the full 90-day window, then relist, usually after a price change or a renovation. As a buyer, check cumulative days on market and the price history before treating a "new" listing as new. A home you've seen before with a reset clock is often the same house at a lower price than where it started, and that history is useful in your negotiation.