My careful spine work turned my bindings around
I used to zip through rounding and backing, treating it like a quick job. That led to books with weak spines that would not stay closed. So I stopped rushing and now spend a solid hour on each spine with a hammer. I shape it slowly, checking the curve often. This change made my books open perfectly and last way longer. People tell me they feel solid and well made. Skipping this care makes for a bad book that falls apart fast. If you want quality, you must give the spine real time and focus.