Well nowadays if you repeat the same thing 8-16 times...issa hit
Have a few of those super repetitive but don't be afraid to mix it up and have hooks that actually have a train of thought versus straight jumping into your phrase...actual choruses. In rap we replace the term "chorus" with "hook" but that's actually the phrase within the chorus that is supposed to stick and "hook" you in.
I don't listen to a boatload of R&B but I look to it for chorus building. Sometimes you can be catchy with your melody/rhythm and vocal performance rather than repetition. Examples would be something like "Paranoid" by Ty Dollar $ or "Up & Down" by T-Pain. A rapped version maybe something like "Stronger" by Kanye West.
If you're going to have a single hook within the chorus break it in half try to always place it in the same spot within each 4 bars. If the catchphrase comes on bar 1, then it needs to come on bar 5. If it's bar 4, bring it back on bar 8. I can't think of an example right now.
Then sometimes you can build up for the first half with a train of thought, then get repetitive for the second half. Examples would be Drake's "Controlla" or "Hotline Bling".
I feel like I was rambling on but I hope this helps some.