How necessary are rubber boots for the front strut inserts?

[BigKriss]

part number 10 (http://realoem.com/bmw/showparts.do?model=HD22&mospid=47382&btnr=31_0121&hg=31&fg=10)

[peks]

they probably keep bigger junk from getting at the seal on the insert, and maybe provide a small compressive pressure to hold the bump stop together if you bottom out hard. cant imagine they terribly important but i dont see why you wouldnt use them on a stock setup

[tim s]

tim s.

[BillionPa]

considering they physically connect to the bumpstop (i know i just assembled some) and the bilsteins bumpstops are internal, where the hell do they go?

[yaofeng]

My 525i has the rubber boots from my SAAB 9k. It is not a perfect match I know. I installed them two weeks ago. The Sachs inserts came bare. I wanted to get them installed and didn't want to wait. I happen to have a pair of front struts from my 9000 in the garage so I took the rubber boot.

[joshua43214]

If you live in a very dusty area, they are rather important. they will significantly prolong the life of the shock. If you where there is not much dust, you can probably get by without