Default Would reinstalling from scratch help with performance?

The last two months my s3 has been performing terribly. I was on custom ROMs for over a year and made the switch back to stock which made my s3 feel like a new phone. But the last two months is a different story. I can't figure out why but things keep stalling and I find myself restarting my phone more often than I would want to

Anyway, I'm wondering whether reinstalling the stock ROM would help any bit

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