According to Honda (Helm service manual), the brake bleed pattern is left front, right front, right rear, left rear. I've done mine 10+ times, and it works for me.

If you don't bleed your brakes, your braking system will slowly degrade in performance and the contaminated fluid will deteriorate seals and metal parts more quickly than fresh brake fluid would. Since brakes are the most important system in the car, a prudent owner WILL change their fluid at regualr intervals.

 

What Joshua said on the pattern.

As to when to add more fluid, you need to be sure that the float doesn't get to the bottom of the reservoir, or you'll get air into the system and wind up with mushy brakes, so add more fluid whenever the level gets half way down or so. And pour the new fluid slowly so you don't make bubbles.