You’ve been working as a DBA for X number of years. How do you know you’re good at it? Heck, you’ve been doing any sort of job for a while. How can you measure whether or not you’re competent?
The single best measure isn’t how much work you do, your accomplishments, the number of databases designed, whatever measure you have. That’s not it. The real measure, the one that counts, how do you perform when everything goes south? When that server goes offline or that database develops corruption or that SSIS package fails or, heck, you get a request to fix something that’s broken, even non-technical stuff like an incorrect W-2 form (fighting this battle currently)? Did you run around like your hair was on fire? Did you sit there stunned into immobility? Did you incorrectly read and interpret the requests and send a new copy of the same, uncorrected, W-2 form (again)?
Or, did you sigh, roll up your sleeves, spit on your hands, and get the problem fixed?
If you did that last thing, you’re good at your job.
Let’s face it, just about anyone can set up a server, install SQL Server, set up backups and then sit there monitoring them for the next five years. The test is not the day-to-day functions. The test is the abnormal, the broken, the wrong. I know people who’ve never had to fix a W-2 form, uh, I mean, a corrupt database. They’ll say, “Yeah, never happened, so I haven’t really looked at what to do about it.”