All 2st How often Should I change out brake fluid?

Got an 09 wr300 and in the past with other bikes never bothered with it but maybe every other year if that. Well lately been riding a heck alot more than before with some more hardcore riders. Solid intermediate rider riding every other weekend throughout the year with the summer mainly riding switchbacks in the mtns(so I am making them suckers cook). Maybe have only 500 miles on the bike.
Yet last weekend coming down the last swtichbacks of a mtn front brake completely disappears. Thank god I only had about 200 yards to finish the ride or I could have been screwed. Everyone tells me its dirty fluid and they change theirs out ever 6 months or so. After the brakes cooled they now act like normal and pads are just fine. I will change out the fluid with quality dot 5.0 stuff but now I am just a tad paranoid. Opinions?

Check your rear brake fluid, the colour will give you a good indication if your fluid is fryed. I change my fluid every 6 months

Boiling front brakes isn't that uncommon especially if you use disc covers (cured by extra venting holes) or haven't changed brake fluid in a while or running pads under half way which causes more fluid to heat up in the calliper due to lower pad thickness - hard riding with a lot of long downhills, no airflow is all it needs to boil them.

You aren't dragging the front brakes unknowingly?

That's something I have been guilty of also, will be adding it to my maintenance list. Most of us here in FL, especially my brake dragging friends, have been using Motul 600 with good success.

Motul RBF600, IMO, is the best on the market but absorbs moisture a little easily.

PS. If you wanting to run 5.0, you need to thoroughly flush the old fluid out as 5.0 doesn't mix with DOT 3,4 or 5.1

DO NOT USE FULL SILICONE DOT 5 FLUID IN THE BREMBO BRAKE SYSTEM! The silicone fluid will eat the orings in the Brembo brake system.

http://www.cyclebrakes.com/html/brembo_tech_info.html

Dirty brake fluid is a no, no. Like evryone has said it is easily neglected . Depending on how much I ride i do mine every six months to a year.

Change in twice a year. It takes about 10min per cylinder.

FWIW, thanks for starting this as it made me decide to flush both Husky's brakes this weekend.

I always look at the color. It's almost clear when it's new and as it absorbs moisture and gets hot it gets darker so when it starts looking dark I change it.