1. Lack of holistic cross-functional advice.  (Your various subject matter experts don't discuss your situation as a team.) 
2. Not executing holistic advice once you have it. 

That's it - those two cover it.   I know that some of you are looking for very specific items to see if you are doing something wrong.    OK, OK, I'll list some - but this is not advice to you, because it may not apply to you.   It does not replace holistic advice from a collaborating team!   We even get second opinions from among the experts to be absolutely sure! 

1. Inadequate or no estate plan.
2. Business owners not obtaining the full value from their business(es) due to less than optimum income and asset protection.  (Less than inadequate tax planning, inadequate succession planning and/or not coordinated with their estate planning.)   Often this is in the realm of hundreds of thousands of dollars "left at the table".    This requires advanced planning led by a qualified attorney, but working with client's expert team members. 
3. No umbrella liability coverage. 
4. Too much, too little, too costly, missing, not needed, poor quality or inappropriate insurance (across all types).
5. No established goals.  (You need to know the destination to arrive there.) 
6. Savings rate to achieve future goals unknown. (No goals and financial projection.) 
7. Paying excess/hidden fees, upfront fees, transaction fees, exit fees - or other fees that could have been avoided.   
8. Poor investment strategy: individual stocks, actively managed retail mutual funds, inadequate diversification, risky fixed income positions, invested assets needed in less than 3 years.  (When #7 or #8 happens it often means you are being sold products rather than receiving advice.)  
9. Too much or too little cash reserves.  (3-12 months expenses pre-retirement, 3-5 years expenses in retirement)