Redoing veneers, a good idea? Risky?

Porcelain veneers can be replaced multiple times provided there is enough healthy tooth structure under the existing veneers. If you opt to have your veneers replaced, an experienced cosmetic dentist could carefully do so, thereby removing little to no additional tooth structure. If you have concerns about your current veneers, I would recommend returning to the dentist who placed them or consider getting a second opinion. I hope this helps. Click save on the save button below my name, so that you may ask me more questions in the future.

Experienced and trained in cosmetics dentists should be able to remake veneers uneventfully, assuming the remaining tooth structure is sound and adequate.  If the previous dentist was inexperienced, it is possible what is left is a challenge to fix.Having said that, even "perfect" cases can be picked apart (even by the skilled dentist on the day they are bonded).  While I see things that could be improved, the photos are NOT as bad as some I have seen.Yes, there are limits to how many times veneers can be replaced, but we are talking 4-5 times, not 1-2.  Each set should last many years (some of my cases are at the 20 year range and still going strong).  If done well, they should only need to be redone 1-2 more times (if EVER).

My 1st question is why are you wanting them redone? Typically, 8 veneers should not affect your bite and they don't look that bad. (though your gums look red where they meet the porcelain) If you were to have then redone, they could be carefully removed thereby conserving enamel and new ones made. The issue is how much tooth was removed in order to place them the 1st time. If it was conservative and not much enamel was removed, you have a better chance to remake them and have them last predictably. If, however, there is minimal enamel, or if your bite is such that they can't be done predictably, you can have crowns done and that can also address your bite better. If you have further questions, please feel free to get in touch. 

It is true that every time restorations are redone there is the risk of more tooth structure being removed. It is possible that the bond will not be as strong but it also traumatic to the tooth and can cause the need for root canals in the future. From the pictures posted it is impossible to determine the quality of your current veneers. i suggest getting a consultation by one or more reputable dentists who have experience in not just cosmetics but who understand how your bite is supposed to fit together. It  is very important to have a comfortable and healthy bite as part of the new outcome of your case. 

If they are removed carefully under magnification, only a slight amount of additional tooth structure will be lost.  A lot depends on how they were first prepped.  The veneers look okay, but not outstanding.  You should be able to get a better result with an experienced cosmetic dentist.