Does Rolo's Geass have no Limits? Rolo has been using his Geass since he was very young and using it beyond limits; for various missions and assasinations again and again. But he never lost control over the Geass like Lelouch and Mao. Also if he had lost control before dying then what would be his situation if he had used it infinitely? Would he stop the time around him forever?
Forever would have been impossible. The weakness to Rolo's time stopping Geass is that it also stops his heart, so he'd die quickly enough from it being in permanent use, which in turn would stop the geass. Same goes for him overusing it. The limit of his geass comes from a sort of body-based time limit (surviving while his heart is stopped) preventing extended use, rather than a limit of the power itself. Below is a quote from this page, which I've spoilered out for plot reasons.


   Its weakness was that it stopped Rolo's heart when used, limiting its activation to short bursts. A large number of people was also more difficult to stop, as Rolo was exhausted after he projected a field encompassing a majority of the school's campus. Finally, this Geass was unable to stop inanimate objects or physical phenomena such as speed and momentum. Rolo ultimately died when he overused his power in a short amount of time.