Your plumber can look for leaks, look for surface rust, but he cant tell what kind of shape the inside is in without opening it up, and personally, if I weren't having a problem, I would save it until I did. If you have really soft water, you could get a lot of usage out of your water heater. About the only routine maintenance is to open one up and scrape out the sediment that is rarely worth the effort. (I have never done it on my heater.) If you have soft water you won't have any significant sediment. You might have him check to see that your T&P valve (emergency Temperature and Pressure relief valve) is working and that the line is clear, that takes about ten seconds. Cross your fingers, maybe you can go ten more years!
If he tells you, "Oh My God, this is ten years old, you have to replace it!" smile and tell him, "maybe later." 
Edit history
Recommendations
0 members have recommended this reply (displayed in chronological order):
= new reply since forum marked as read