Protecting children from all failure is one of the highest-cost parenting choices. Small failures (missed homework, lost belongings, fall-outs with friends) build resilience and problem-solving skills. Adults who never failed as children often struggle with adult setbacks they have no template for.
What small failures build
Recovery skills (the experience of being okay after something goes wrong). Problem-solving (how do I fix this). Self-trust (I handled that, I can handle the next one). Emotional regulation (disappointment is bearable).
Where to start letting failure happen
Forgotten homework: let the school consequence happen rather than rushing it in. Fallouts with friends: don't immediately call other parents to mediate. Missing items: let kids find or replace them rather than always replacing them. Small natural consequences are the curriculum.
Save the rescue energy for actual emergencies. Small failures, navigated, become the foundation of resilient adulthood.