We already had Pyrex bowls at home, but without the lids.  We were constanly using seran wrap over the bowls when letting bread rise, cookie dough chill or just for storing leftovers.  When we saw the set with the lids, we had to order it.  We have not been disappointed!  The bowls are heavy duty/great quality. The lids fit on nice and snug (and even fit on our other Pyrex bowls, of course). We use these bowls all the time to store things.  And when we aren't using them, they easily stack inside one another!