I have never greased the suspension whilst on holiday, always before and after. Longest trip was 2500 miles and the original standard fit kingpins lasted 34,000 miles on my last car with hard chrome replacements that should last longer. Only done 12,000 miles on my current car so who knows how long they will last.
I would think, but don't know, that if you use the car regularly the kingpins are lubricated adequately but leave the car for weeks or months without a decent run and you are going to have problems.