I have found this to be very helpful:
https://www.luxfercylinders.com/img/rm_img/blog_img/455/attachments/1/scubaguide.pdf
Based upon the information in this file I condemned two of my alumimun 80s. All of my steel tanks (8, total) passed my inspection and four recently passed the inspection of the hydro test guy. I don't normally inspect my tanks at exactly one year mainly because I maintain my compressor and I know that no water is getting into my tanks, but I do look inside every 15 to 18 months or so, depending upon how much the particular tanks has been used.
I have my own compressor and I'm not going to fill or use any tank that I think is questionable. Normally I will just do one dive locally but I'm thinking of getting some generic VIP stickers so when I go to Catalina I can get a fill and do a second dive. Do you know if it's true that a sticker is not required for the first year after the hydro test?
With what my LDS charges for a VIP, Hydro Test, Air Fill, and Tumbling I would probably be over halfway to buying a new tank. And then they want to do Valve Service too.