Lumineers or durathin veneers? which one requires very less amount of tooth removal?

Same: With the advance of bonding system, how thin the veneer is becoming a nonfactor. I am more concern with the esthetic and the hardness of the material. Lithium disillicate is the best in term of durability, but then the esthetic is not as beautiful as the more translucent material such as feldspathic or empress. It is not how much but where we remove the enamel that gives the best outcome.

Prep Less-Prepless: Most veneers can be placed with or without tooth reduction. In fact the earliest "bonded" composite veneers did not have any reduction. While it is better to conservativly maintain natural enamel for bonding, esthetic factors verses a patient's desires regarding enamel reduction dictate the procedure's direction. My rule is minimum "prep less" reduction to obtain the maximum esthetic results!

It depends : These are both used for prepless or minimal prep veneers. I do agree with other doctors that the less that is prepped the better as it conserves tooth structure. This being said in some cases i feel prepless veneers are contraindicated as they will make the teeth appear bulky. If your teeth are somewhat tucked in then these can be great. Personally, durathin has better esthetics.

Not applicable: Both veneers are considered to be no-prep veneers, which means no tooth structure is removed to place these veneers.

Both no-prep: Just make sure when you have no prep veneers, you don't have the outcome of bulky looking teeth, or big, square, chicklet looking teeth, make sure the axial inclinations, incisal and cervical embrasures and gradation, the translucency, primary and secondary anatomy of the veneers, the anterior characteristics and value, chroma, hue are all to your liking.