Power steering
 

Is the power steering fluid something that goes low on the e53 3.0 m54 models.. In NY we have been having some very harsh winter days so I'm not sure, I would open the hood but it won't stop snowing sigh. I would just like to know if it is common for it to be low on fluid

If there's a leak...yes you could lose PS fluid.

Unfortunately you really need to check both under the hood and under the vehicle for sign(s) of PS fluid leak(s).

You need to idle first (like 5mins), check the PS hoses and PS Lines.
In my case PS suction hose and PS line to radiator was the culprit.
I also replaced the PS reservoir (as a preventive maintenance)
============================================

Edit: TEMP FIX until the warm weather hits :)

OR you can just top off the PS fluid (ATF or CHF 11s) - check you vehicle PS reservoir label.
(turn the wheel max left and max right - this activates the PS pump to circulate the fluid), check the level again.

Yes,if any doubts ,it is good to check from time to time.