Holy balls Tails is like the most useless motherf***er.
I should have like 19 emeralds by now
I'll mention this again...!
Tails cannot lose you rings! He can only lose what he picked up, which means you missed them. If you didn't have Tails, you'd never have those rings to lose in the first place.
Legitimate complaints exist for Tails however. For instance, how he'll hit a boss and make it invincible for a second, causing you to fall through and die in a pit (Chemical Zone, Angel Island) or lose rings (Oil Ocean, probably others).