Which benefits must be filed for in person at the Social Security office?

The requirement to file in person at a Social Security office primarily applies to Supplemental Security Income (SSI) benefits due to the nature of the eligibility determination process. SSI involves a need-based assessment that considers various factors, including income and resources, which often necessitates a thorough review of the applicant's specific situation that can be more effectively discussed in person.

In contrast, while disability benefits and retirement benefits can involve a significant amount of documentation, they can often be filed online or over the phone, which provides greater flexibility for applicants. Children and surviving spouse benefits typically follow similar protocols to retirement benefits, allowing for a more streamlined application process that does not require an in-person visit.

Therefore, in-person filing is specifically aligned with the requirements for Supplemental Security Income, making it the correct choice in this context.