You can leave it for a while if you want. The only consequence is a higher likelihood that next time you get brakes done, you will have to work on the calipers as well. A few months won't make any significant difference in that.

Not a big job, just putting the vehicle up on a hoist, adding fluid, and bleeding the system at each wheel, unless they get air in the system. Then it becomes a bigger job, due to the inability to bleed the ABS control valve directly.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue