A client told me my headbands were 'too tight for a proper lay-flat' and now I always check the swell before sewing.
I was binding a custom journal for a regular last month, and when she picked it up she said, 'Emma, the text block feels stiff, like it's fighting to open,' which made me realize I'd been pulling my linen thread too tight during sewing, not accounting for the paper swell from the PVA (a mistake I'd made for probably two years).