DebiTN

I got a used 2006 Equinox 3.4L Nov 2012. Mid Sept 2013, I had an oil pressure issue which became know w/my Oct inspection. I was told oil pressure switch get replaced in vehicles about every 5 years. Does this sound correct?
Also spark plugs replacement:
A.Told spark plugs do not need replaced till
1. Engine service light comes on
2. Vehicle has the 100,000 miles or more.

B. Go with Iridium/Spark Plug. Auto Zone rep said these were recommend for this vehicle.
Yet a previous post here recommended Name brand plugs, perhaps other than Iridium/Spark Plugs[?]. Any thoughts about Iridium/Spark Plugs.
These are new choices for me, yet so is having an Equinox to repair.
Having to replace the CD entertainment unit this weekend. CD does not play,most likely "A plastic part" broken[6 months from purchase date] :~{
Thanks