Should I have a crown or a veneer?
A crown covers the whole tooth and is used when a large amount of tooth structure is missing, cracked or heavily filled. A veneer covers the front surface only and is used mainly for appearance on teeth that are structurally sound. The choice follows how much healthy tooth remains.
How much tooth is left
This is the question that decides most cases. A veneer is a thin ceramic facing bonded to the front of a tooth, and it relies on that tooth being largely intact underneath. A crown wraps the tooth completely and takes over its structural job. If a tooth has a large old filling, a fracture line, a root canal or missing cusps, a facing has nothing dependable to bond to, and a crown is usually the appropriate answer.
Both require preparation of the tooth, and both are irreversible once enamel has been reduced. A veneer removes less. That is a real advantage, and it is only available while the tooth still has enough enamel to preserve.
What each one is good at
Veneers are used to change color where whitening has not worked, to close small gaps, to correct minor rotations, and to lengthen teeth that have worn slightly at the edges. Crowns are used to hold a cracked tooth together, to restore a tooth after root canal treatment, to replace failing large restorations, and to carry a bridge or sit on an implant.
There is a middle ground. Partial coverage restorations such as onlays cover the biting surface and some of the walls without taking the whole tooth, and they are worth asking about when a crown feels like more than the tooth needs.
Where the bite comes in
Front teeth guide the jaw when it moves sideways and forward, so any restoration on them takes that load. The way the teeth meet has to be assessed before the design is settled. Where several teeth are being treated at once, or where wear has already changed the bite, the case moves from a cosmetic decision to a restorative one and should be planned as a whole.
Materials and longevity
Modern ceramics can be made to look convincing in both forms, and the material choice is driven by the load the restoration has to carry and by how much space is available. No restoration lasts indefinitely. Margins can decay, ceramic can chip, and a night guard is frequently recommended for people who grind. Reported service lives vary widely between studies and between patients, so a specific number of years is not something that can be honestly promised in advance.