Gambling operators have introduced responsible gambling (RG) tools to protect people from harm. Two examples of RG tools are mandatory play breaks and personalized feedback. In this study, the researchers tested the impact of different lengths of mandatory play breaks on gambling behaviour using a real-world experiment. They also tested if including personalized feedback with mandatory play breaks increased their effectiveness. The participants were 21,129 online players of Norsk Tipping. These players triggered a total of 156,989 mandatory play breaks during the study period. The mandatory play breaks were triggered after 60 minutes of gambling. The breaks varied in length from 90 seconds, 5 minutes, and 15 minutes. A 15-minute mandatory break led to the longest voluntary play pause. The inclusion of personalized feedback did not increase the duration of the pause. Amount wagered decreased for some participants after a break, but a longer break did not lead to greater decrease.