does this make sense

was looking on the net and found this link for changing brake fluid \
http://www.clubgp.com/cgi-asp/mods.asp?modid=7

what do you guys think. if it seems okay ill do it

gravity bleeding. It works to some extent at removing the old brake fluid, but probably not very effective with trac control and abs pumps.

Unless there is moisture or contamination, there is no reason to change brake fluid for the most part. Some people do, and there are no ill effects, but it's not necessary. I love it when garages say you're due for a brake fluid flush!

what about when it starts looking dark greenish?

That would be contamination, normally from moisture or someone isn't opening the bleeders when changing brake pads, and is pushing the nasty fluid from the caliper pistons back up the system (not good on ABS vehicles).