First, let me explain that my husband and I both fall in that 47% as quoted (NOT as meant). I have been on SSDI for almost 12 years. My husband was medically retired and put on a mix of SSDI & LTD. Since his LTD is non-taxable by the state and the federal government, what we make with JUST SSDI falls below the cutoff to pay at all.
We would prefer to work but life didn't deal us that hand...we got this hand instead.
We recently worked early election here in TN. We actually made a goodly sum so we made a trip to the social security office and asked about the effect that income would have.
How it breaks down is MOST (NOT ALL as it depends on the type of disability you have/receive) people getting SS can work up to $1010 without it being considered Substantial Gainful Activity. SS publication is here.
IF you break thru that, they look at the number of months involved. Can not do 9 months in a row and still get SSDI, but one month won't affect your benefits.
So while we did make more than the limit for one month, it was a very short time/part time job.