All of our money is in joint accounts - we have never had "mine" or "yours" accounts. Some of our investments, both now and in the past have been in individual names but that is for tax purposes only. Altho sometimes I like to joke with DH about our current investment property being mine until he reminds me that I can then have the mortgage that goes with it!

My parents on the other hand for as long as I can remember have always had separate accts, and dad especially gets really possessive about "his" money. Mum keeps her money separate from dad cause he is EXTREMELY irresponsible and frivolous and if he had access to all the incoming moneys he would just spend it with no consideration to bills, food etc. So for them it works.