How to Care for Them?
Chafe is the nemesis of any line (good or bad).
Although wear is inevitable, it's not uncontrollable. In a permanent docking arrangement, the chafe problem is most chronic.
First, chafe-proof your boat as you would childproof your home. Examine chocks, cleats, bitts, posts, and other hardware for rough edges. Next, consider how you lead the lines, being careful to avoid acute angles, which present opportunities for abrasion. Last, get defensive. Chafe protection can range from heavy cloth such as old blue jeans wrapped around the line at the point of contact to ready made chafe guards attached to the line where it passes through the chocks.
Research has shown that chafing material that doesn't let moisture and air into the line can result in excessive heat buildup as the line moves back and forth within the material. Therefore, it would be important to avoid using materials that can do this, such as a plastic or rubber hose. TideMinders help avoid chafe where the line goes around the pilings.
Whether you're in your permanent slip, or just passing through, regularly check the condition of your lines for signs of wear. The investment in your boat could depend on it.
Size Matters
As a general rule docklines should equal two-thirds of your boat's overall length. Spring lines should be considerably longer. You will need to be able to use these to bring your boat alongside while docking. You may need to pay the spring line out to ease your boat to a stop in the right position and as the helmsperson brings the boat alongside. This is an art in itself, but very important. You should have lines of various lengths available to use depending on the circumstances as you come alongside a dock and the pilings and cleats on the dock. The shortest should be approximately the same length as your boat.