Sure, but the only qualification to be on IBR is that your IBR payment isn't higher than your standard repayment payment, so it's less a qualification and more

Sure, but the only qualification to be on IBR is that your IBR payment isn't higher than your standard repayment payment, so it's less a qualification and more a guardrail. Filling out a single form every year on a website is not the worse fate. The debt is of course on your credit report, but if you are making payments, more likely than not it's going to be beneficial, as young people are unlikely to have other debts that are considered "old". My own student loans carried the "age of credit" criteria on my credit report for a while. They are a percentage of income, but that is no different than the UK version. And to be fair to IBR, it's more nuanced that that - the income cutoff for the percentage varies state-by-state (so, someone in New York has a much higher cutoff than someone in Arkansas).