Glass shows everything
Glass is unforgiving. Fingerprints on an entry door, film on a partition, streaks across a storefront — these are visible from further away than any other kind of dirt, and they undo the impression the rest of a clean building makes.
Interior glass, entry doors, and partitions are usually handled on a schedule alongside recurring cleaning. Anything beyond that depends on the building and how the glass can be safely reached, so it's worth a conversation about your specific site.