You can't afford to go without regular medical care if you hope to keep SSDI benefits. Often going without medical documentation of ongoing issues is interpreted by the SSA as an indicator that there must have been improvement in your condition and care is no longer needed (not that you can't afford it).

I know that the cost of medical insurance, copays, and meds can take a big bite out of our monthly checks, but regular medical care is a necessity for most people who are disabled, and definitely for those who need to show the SSA that their disability is ongoing.