I see a lot of discussion regarding how to and how not to clean the MAF. I'll be honest, I've never cleaned mine. I have ~140,000km on my 2000 3.8, never had a code leading to the MAF. I'm wondering if people routinely, yearly or ever clean this thing as routine maintenance. With the cost of gas and vehicles I like mine running as problem free as possible.

thoughts?

If you have a problem....then cleaning the MAF is a good thing to try before just replacing it.
I have a couple of pictures posted that show how to hold the unit to do this.
Basically, you hold the whole unit (I don't recommend taking it apart....unnecessary) so that you are looking DOWN into the unit through the screen.....as viewed from the air cleaner side......
You will see a plastic cross member...with a hole it.....at one end.
Tilt the unit very slightly so that the cross member slopes down from the hole that faces you........

On the opposite side......at the other end.....is another hole that faces away from you.
So air enters the hole that is facing you......flows through the cross member and exits out the hole at the other end.....facing away from you..

The idea is to spray the NON-RESIDUE ELECTRONIC CLEANER into the hole that is facing you.....and let it run through the hollow cross member....cleaning the 2 sensors inside.....and the fluid then runs out the hole at the other end.

There have been reports that folks who over oil filters like the K&N can end up with a oil film over the sensors inside the MAF unit....which can lead to incorrect readings.

My advice is to look at the cross member inside the MAF unit when you check/change the air filter.
If you see dust on it.....you might clean the MAF as I mention.
If you do not see any dust/oil/etc and you have no issues......then leave it as it is.