An additional note on IBR and loan forgiveness after 25 years.
AS OF NOW, when this happens, there is an IRS form that will mitigate what (if anything) you own in income taxes based on what assets you actually have in the year the debt is forgiven.
For someone with near to nothing, there may be no tax liability. However, there's no guarantee this will be the case in the year when YOUR loans are to be forgiven.
Also, there is a standing Bankruptcy case where a woman was able to get student loans discharged, and while the creditor argued that she could use IBR, the judge held that the tax liability on someone of such limited means in and of itself was an "undue hardship" qualifying the debt for bankruptcy relief. IRS debts/obligations ARE NOT subject to bankruptcy discharge once they are incurred.