I do use a time tracker (tracker.toptal.com <= the UI/entry is pretty good). What I am having a hard time doing is planning the next days (can I mow the lawn an

I do use a time tracker (tracker.toptal.com <= the UI/entry is pretty good). What I am having a hard time doing is planning the next days (can I mow the lawn and go to the hairdresser and still have time to put in x amount of work).