Definitely sterilize the jars and lids. It is not hard to do. Scald the jars in the canning bath and the lids and rings in a smaller pan. Leave them in the hot water until ready to fill and seal.

Clip-and-gasket jars and lids are risky, as the seal is not dependable and you can not absolutely tell if the seal is complete. With canning lids and rings, you know the vaccum seal is good if the lid is slightly concave. (after the jars are removed from the bath or pressure canner, you will often hear a chorus of pops as the seals complete.) Weeks or even months later, when you go to use the product, you can push on the lid to insure the seal has held. If it gives even a little when you push down on the center of the lid, the vacuum seal has broken, and you need to toss the contents.

After the jars have completely cooled, by the way, you can remove the screw-down ring, and reuse it. (never reuse a lid, however.)    It is probably best to remove the ring for long term storage. In humid conditions, moisture can be trapped between the ring and lid which can lead to rust. and eventually, a broken seal.

It is safe to use jars that can take heat other than canning jars, but only if they are sized so that canning lids and rings fit the necks well, and the necks are fully threaded. Many commercial jelly, mustard, or condiment jars do not have sufficient neck depth or threading to insure a good and lasting vacuum seal.