We have double berths and a lot of surge as we have southerly exposure to the Singapore
straits and ship wakes hit us a lot. I have had docklines last as little as 2 months.
I was also getting knocked against the pier a lot and actually burst a fender!
I took a diagram from StuM's last link and penciled in what I have done.
I used to run the springs from forward and aft cleats
but the lines chaffed seriously on the hull paint
and I had to figure out how to hold the boat off the dock
and stop the lines from chaffing the boat.
I added (am adding) midships cleats and I have been for a while putting a breast and spring from the port stern to the head
of the dock. The spring from the stern has to be snug but I have figured it out so the starboard quarter doesn't hit the dock.
This arrangement may not work
for a longer boat as the geometry isn't right.
Every line also needs a serious snubber where I am at.
Our marina probably has the worst conditions I've ever regularly been in.