My policy: if the buy-box price (or a little less) looks satisfactory to me, send it in. I don't worry much about sales rank, unless I have a lot to sell (I usually send in 1 of this, 3 of that... sometimes 5 or 6 of an item, but rarely more). If you match the buy-box price for sales rank 20,000 or less (and some d-bag doesn't have his software set to automatically undercut you) items usually sell within the first few hours. Sales rank 40,000 or 70,000 may take a few days. Sales rank 150,000 may take a few weeks (or may sell quickly... you never know). I am only wary of slower selling items (sales rank > 100,000 ) in that I won't send in multiples of those items... no need to send in 4 or 6 of those... they may be in storage a month or two, and I don't like storage fees. If the one you send in sells quickly, send in another.