unfortunately thats what it takes to get rings.....(short answer)
the long answer is that rings can be varying sizes, different amounts of metal, different metals altogether, deep or shallow. that makes IDing them pretty doggone tough. Anybody who has located lots of rings will tell you they probably dig a bucket full of trash for every ring!
On the good side, it only takes one good one to pay for your detector!
It's a good idea, when you find one, to try and locate the owner if there's any identifying inscriptions. Class rings are the easiest, and getting them back to their owners is worth its weight in gold. It's a good feeling!
If the owner can't be found, well then.... what you do with it is up to you.