“How durable is the bonding material, and what is the typical lifespan of a cosmetic bond?”

Is durable and functional but life span not for long time depending on what materials you used ?
Life span from 1 year to 5 years and how you take care of it

There is a huge variation in durability. Someone who grinds or clenched their teeth will not get nearly as long as bonding for someone who does not. Remembering that the binding is a Jewel not a Tool does help prolong the restoration

Cosmetic bonding is relatively durable but not as long-lasting as other restorations like crowns. The bonding material is made of composite resin, which can wear down over time. Typically, a cosmetic bond lasts **5 to 10 years**, depending on factors like oral hygiene, chewing habits, and whether you grind your teeth. Regular touch-ups or reapplications may be necessary to maintain its appearance and function.