[Tom]

Comebacks work the first time but the artist has to be big in the first place. Rihanna would be fine to take a short break.

Britney Spears & Christina Aguilera both took breaks when they were big and returned bigger with their first comeback, but it didn't work for their 38th comeback and now they're both pretty irrelevant has beens. Longevity isn't an issue when you consider people like Beyonce and to some extent Kelly Rowland have worked pretty much for the best part of the last decade without a break and are still on top