We shear our rabbits every ninety days. You can expect your rabbits hair to grow 1+ inches per month and 3 months should give a perfect spinning length. German Angoras have synchronized hair growth meaning they grow only one coat at a time. When they are sheared, it's down to the skin and start over. If done every ninety days, they are sheared before any significant matting can occur. Recommended is a 45 day maintenance from around the runt and ear area as these areas tend to mat first. This is also a good time to clip nails.  

German Angoras generally are not brushed or plucked. They may be blown out with a pet blower, wet vac on reverse or air compressor. 

I tend to begin blow outs in the third month in preparation for shearing. 

German Angoras can be sheared using scissors or clippers. I use clippers as scissors can catch the skin no matter how careful we are and clippers are significantly faster and more consistent. 

The clippers do not need to be expensive. I use the brands Gimar or Heapets depending on what is currently available on Amazon. These are rechargeable clippers, lightweight without a cord. I normally shear on the .8 setting. These clippers do not require sharpening and the cost of a new pair is generally less than sharpening 2 or 3 blades at a time.

After shearing attention needs to be paid to keeping bunny warm for 2-3 weeks after while new hair grows in. My bunnies are house bunnies and I just use a heat lamp. The IAGARB webpage offers patterns for felt jackets you can make to cover your bunny plus other tips for keeping them warm.