My surgeon says a mommy makeover will take 8 hours. Is this safe?

Mommy makeovers combine several procedures in a single setting so they are longer cases. Board certified plastic surgeons routinely perform these procedures safely either in accredited surgical centers or hospitals with the appropriate team members (anesthesiologists/nurses/assistants, etc.) and appropriate postop/overnight monitoring. 

It's hard to say without knowing a little more about your situation.  How many procedures are part of the mommy makeover?  If we use the standard pairing, a breast procedure and tummy tuck, that could take as little as 2-3 hours or up to 4-5 hours depending on the extent of each part of the surgery.  I scratch my head as to how one could get to 8 hours unless we are talking about additional procedures such as face/arms/thighs.  In that case, the extent of surgery presents a bit of concern and can lead to a higher chance of postoperative difficulties.  I favor limiting surgery to 6 hrs (FL rules allow up to 8) if possible.  That allows for some extra time if needed and limits the difficulty of recovery.  I have found that nearly 100% of patients can be safely discharged to home with a very low chance of issues when following these and other principles.  

Depending on the type of operations that are performed in the efficiency of the surgeon a mommy makeover may take eight hours. Of and by itself this is not a contraindication but in my opinion you should spend the night in the care of a skilled nurse