In my experience:
From Canada or USA-- 20 days
From Europe-- 10 to 15 days.
From Asia -- 30 days or more.
EBay has a Buyer Protection Plan. If your item has not arrived by the time above, first contact the seller and ask for the shipping date, the shipping service and the Delivery Confirmation number.
Don't worry if there is no DC number. It is helpful to the seller, not to you.
Do worry if the seller promises a replacement. It will never arrive (a fairly recent scam).
If the item has not arrived by Day 43 after purchase, start an Item Not Received dispute and get your money back.