Yes I only had one zerk per u-joint so the cups weren't getting fully lubed and had some wear as shown in my pictures. I'd guess with good lubing the joints could last hundreds of thousands of miles.
My reason for writing was mostly to say changing u-joints can be done if you don't mind the effort and dirtiness of the work. The shop work (of pressing out the old part and installing new parts) cost $60. I paid $53 for each Spicer brand joint. Total cost less than $170
Next on my list is fixing a leaky transfer pump. I have read about fixing that on the forum so will be taking that on soon. Just one more thing to fix......................always.