I think when you really need/want a DBA is when you're at a point where either you need redundancy/scale or have to remain up. Most developers aren't going to

I think when you really need/want a DBA is when you're at a point where either you need redundancy/scale or have to remain up. Most developers aren't going to become that familiar with the details of maintenance and scale for any number of different database platforms. I think MS-SQL does better than most at enabling the developer+dba role, but even then there's a lot of relatively specialized knowledge. More so with the likes of Oracle or DB2.