Might as well get the whole links (left, right, center) when they are done for.

The boots to watch, are the lower ball joint boots. It's not that the balljoints are expensive....it's that you need a special tool to get the new ones in (ie go to shop, or rent one).

Saying how long front end components are going to last is......Well... you might as well call Madam Cleo, since it depends on your roads and how you drive, and what you hit and avoid.
I feel comfortable saying that most lower balljoints will need replacing around 130k, the uppers will usually last quite a bit longer than their bushings (it's more of a control arm/ball joint combo). The tie rods might make it to see 200k.
Besides the above mentioned road conditions and driving patterns, your location will play a large part in how long parts will last - not my prognostications.

__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D