My sister buys needles in bulk - so much cheaper - we split an order. You do not want a leather needle. Those have a special point on them and will tear the fabric if it has any stress. If you are sewing heavy stuff get some 16s or 18s. I buy them in bulk and throw them out frequently with out stressing myself out. My commercial walking foot will take a 22 or a 24 but I try to use a 20 - if I'm going through some real heavy stuff I change needles.