if the technical stability is greatly affected then balancing the two (stability and a more streamlined reward approach) , 7 days would make more sense then 24h.
Still, some categories of users fall out of the employee range and fit into a more continual reward expectation: writers, musicians etc. and we might need to respond to their needs too.

On the downside, Trending posts algorithms need to be well thought and will bring their own downsides and benefits.

Edited to remove the 30 days reference which is proposed to be removed.