It is best to bleed the brakes, top off fluid, and change the pads and rotors at the same time. Rarely do all occur at the same time. If you wanted to, you can bleed them. If they don't feel like they need it, then don't owrry about it. However, the best time to top off the fluid is when all pads and rotors are new, so that way the calipers are at their max setting. If you bleed and top off when the pads are worn down, when it comes time to change the pads, you will actually force fluid out of the system.
<span style='color:gray'><span style='font-family:Courier'>1995 e36 3 Series RIP
1999 e46 3 Series BURN IN HELL
2000 MR-S Roadster= Current</span></span>