Cleaning your sewing machine

It is really important to clean and oil(some machines) your sewing machine.  Your sewing machine will only work as good as you take care of it.  If you don't take care of it, it won't work well.  Here is a great video I found on youtube, be sure to watch it.
http://www.youtube.com/watch?v=Fkkl9ZiYlgU&feature=uploademail

Here is a youtube video on how to clean a handcrank sewing machine.
http://www.youtube.com/watch?v=bidpJsAzc2A&feature=results_video&playnext=1&list=PL3E850285CAEF8655

I have also been told to always clean your machine after every quilt and to change your needle after every 8 hours of sewing.  Boy am I bad about both of those things!
Here are pictures of all of my sewing machines!

http://missyscakesandaprons.blogspot.com/2012/10/hand-crank-sewing-machines.html

http://missyscakesandaprons.blogspot.com/2012/01/birdhouse-quilt-update-2.html

I don't think the White works, I'm afraid to plug it in because the chords are so frayed.

http://missyscakesandaprons.blogspot.com/2012/02/i-went-to-that-junk-shop-where-i-got-my.html
http://missyscakesandaprons.blogspot.com/2012/01/treadle-sewing-machine-and-winner.html
Yes, thast's right, you counted 7!  But, one is scary (White), and one is on hold for a friend.  It's brand new, I plugged it in to give it a test run, and it sewed fine for 5 minutes but the feed dogs somehow dropped down just a tiny bit.  I tried the lever to drop them, and they dropped more, but when I tried to bring them back up, they didn't come up all the way.  I've had it for a year, I'm not sure what to do.  So, I only have 5 working machines.

Have a great day ya'll!
Missy