You can decide to send your message specifically during working hours or not, for each channel.
There is no one-size fits all rule to set-up your time restrictions, given your market, your country and the channel; It's really up to you to choose if you want to send messages only specifically during working hours or also during after hours and on Sundays.
From your Carts Guru dashboard, go to:
Retargeting Automation > Settings > Time Restrictions for Messages. After clicking on Configure Restrictions, this window will pop-up.
Follow the video guide here:
Simply select which channels you would like to implement the time restrictions on, and that's it!